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Form  87.— 0.  C.  8. 
Ed.  10-13-11—50,000. 


3—1071 


MANUAL  FOR 
SUBMARINE  MINING 


EDITION  OF  1912 


R.  W.  FINGER. 

2nd  Lieut. Coast  Artillery  Corps 


Registered  Number 
DEC  3      1912 

WASHINGTON 
GOVERNMENT  PRINTING  OFFICE 

1912 


WAR  DEPARTMENT, 

Document  No.  399. 

Office  of  the  Chief  of  Staff. 


Y  oo 


WAR  DEPARTMENT, 
OFFICE  OF  THE  CHIEF  OF  STAFF, 

Washington,  June  29, 1912. 

This  Manual  for  Submarine  Mining,  revised  to  1912,  is 
approved  and  published  for  the  confidential  information  and 
guidance  of  the  Army  of  the  United  States.  Under  no  cir- 
cumstances shall  its  contents  be  divulged  to  persons  not  in 
the  military  or  naval  service  of  the  United  States. 
By  order  of  the  Secretary  of  War: 

WM.  H.  CARTER, 
Major  General,  Acting  Chief  of  Staff. 


447 


OOl^TE^TS. 


Page. 

CHAPTER  I.  Definitions  and  general  principles 7 

II .  Materiel  of  the  system 11 

III.  Loading-room  duties 34 

IV.  Locating  distribution  box,  laying  multiple  cable,  mark- 

ing out  mine  field 42 

V.  Assembling  and  planting  mines 48 

VI.  Test  of  mines  and  apparatus 56 

VII.  Taking  up  mines 62 

VIII.  The  mine  command 65 

APPENDIXES. 

1.  Explosives. . . .'. 69 

2.  Oil  engine  and  generator 77 

3.  Storage  battery , 84 

4.  Submarine-mine  cable 92 

5.  Care  and  preservation  of  materiel 106 

6.  Instructions  for  masters  of  mine  planters 110 

7.  Manual  for  small  boats 114 

8.  Supply  list 120 

5 


CHAPTER  I. 
DEFINITIONS  AND  GENERAL  PRINCIPLES. 

A  submarine  mine  consists  of  an  explosive  charge  inclosed 
in  a  water-tight  case,  and  a  firing  device,  the  whole  intended 
to  be  submerged  in  a  waterway  which  it  is  desired  to  close 
against  the  passage  of  an  enemy's  vessels. 

With  respect  to  the  position  of  the  case  containing  the  ex- 
plosive, submarine  mines  are  of  two  classes,  buoyant  and 
ground. 

In  the  buoyant  mine,  the  case  contains  the  explosive  and 
the  firing  device,  and  has  such  excess  of  buoyancy  that  it 
would  float  were  it  not  held  below  the  surface  by  a  mooring 
rope  and  an  anchor.  The  submergence  is  such  that,  while 
the  mine  wrould  be  struck  by  the  hull  of  a  passing  vessel,  it  is 
not  so  near  the  surface  as  to  be  seen. 

Buoyant  mines  may  be  planted  and  operated  successfully 
in  water  150  feet  deep.  They  should  not,  in  general,  be  used 
where  the  depth  of  water  is  less  than  20  feet. 

In  the  ground  mine,  the  case  contains  the  explosive  and 
the  firing  device,  and  is  heavier  than  the  displaced  water; 
it  therefore  rests  upon  the  bottom  and  requires  no  anchor. 
Ground  mines  are  not  used  where  the  depth  of  water  exceeds 
35  feet. 

With  respect  to  the  means  used  to  fire  them,  mines  may  be 
classed  as  mechanical  and  electrical. 

Electrical  mines  are,  in  turn,  of  two  general  classes,  con- 
trollable— in  which  the  firing  device  is  under  control  after 
the  mine  has  been  fixed  in  position ;  and  noncontrollable — in 
which  no  such  control  is  had. 

Mechanical  and  noncontrollable  electrical  mines  are  in- 
tended to  be  fired  only  by  the  blow  of  a  passing  vessel. 
When  once  in  position  they  are  dangerous  alike  to  friend 

7 


8  SUBMARINE   MINING. 

and  foe,  while  controllable  mines  may  instantly  be  made  safe 
for  friendly  vessels  or  as  quickly  made  dangerous  to  vessels 
of  the  enemy. 

Controllable  electrical  mines  are  arranged  so  as  to  give  a 
signal  to  the  operator  when  they  are  struck.  They  may  be 
set  to  fire  automatically  wjien  struck  or  tampered  with,  or 
may  be  fired  at  the  will  of  the  operator.  In  the  latter  case 
the  firing  may  be  delayed,  in  which  case  the  operator  fires 
the  mine  some  short  interval  after  the  signal  indicates  that 
it  has  been  struck;  or  by  observation,  in  which  case  he  fires 
it  after  the  position-finding  system  shows  that  the  vessel  has 
come  within  the  mine's  destructive  radius.. 

LOCATION   OF   MINES. 

The  considerations  involved  in  the  location  of  mines  are  of 
two  general  classes,  tactical  and  local. 

Tactical  considerations  deal  with  the  position  of  mines 
with  reference  to  the  other  defenses.  Local  considerations 
deal  with  the  width  and  depth  of  the  channel,  the  swiftness 
of  the  current,  the  variation  of  the  tide,  and  the  relative  im- 
portance of  the  harbor. 

Where  ordinary  ship  channels  are  unobstructed  it  is  pos- 
sible for  modern  battleships,  with  their  high  speed  and 
heavy  armor,  to  run  by  shore  batteries,  at  least  in  the  night 
or  during  a  fog;  hence  the  defense  of  such  channels  should 
not  be  left  to  guns  alone. 

On  the  other  hand,  where  mines  are  unprotected  by  the 
fire  of  shore  batteries  it  is  possible  for  an  enemy  to  remove 
or  disable  them. 

Therefore  guns  and  mines,  the  two  elements  of  the  fixed 
defenses  of  a  harbor,  are  mutually  dependent,  and  when  the 
location  of  one  has  been  decided  upon  that  of  the  other  must 
conform  thereto. 

Within  the.  zone  between  4,000  and  8,000  yards  of  the  main 
defense  the  fire  of  heavy  guns  is  destructive  for  warships, 
yet  the  latter  are  at  such  a  distance  that  their  rapid-fire  guns 
will  be  of  little  effect  against  the  batteries. 


SUBMAKINE    MINING.  9 

Moreover,  at  4,000  yards  vessels  are  just  beyond  the  inner 
limit  of  mortar  fire. 

If  possible,  therefore,  hostile  vessels  should  be  held  in  this 
zone  by  some  obstacle.  Such  obstacle  is  afforded  by  a  mine 
field.  ' 

On  the  other  hand,  attacks  upon  a  mine  field  are  most 
liable  to  be  made  by  small  boats  at  night.  If  the  mine  field 
be  at  too  great  a  distance  from  the  defenses,  these  boats  will 
not  be  revealed  by  the  mine  searchlights.  Furthermore,  for 
protection  against  such  attacks,  the  defense  relies  upon 
rapid-fire  guns  of  relatively  limited  range. 

Due  to  the  above  considerations  the  outermost  mines  are 
usually  placed  between  3.000  and  4,500  yards  from  the  main 
defense. 

In  general,  there  should  be  in  each  main  channel  at  least 
three  lines  of  mines. 

ELEMENTS  OF  A  MINE  SYSTEM. 

The  elements  of  a  mine  system  are : 

1.  The  mining  casemate,  consisting  typically  of  four  rooms  : 
( 1 )   The  operating  room,  containing  the  power  panel  and  the 
operating  boards;   (2)  the  engine  room,  containing  the  en- 
gine and  the  generator;    (3)    the  battery  room,  containing 
the   storage  battery;   and    (4)    the   sleeping  room   for  the 
personnel. 

2.  The  multiple  cables,  7  and  19  conductor,  leading  from 
the  casemate  out  to  the  distribution  boxes,  one  of  which  is 
in  the  center  and  rear  of  each  group  of  mines, 

3.  The  single-conductor  cables,  radiating  to  the  front  from 
the  distribution  boxes,  one  leading  to  each  mine. 

4.  The  mines,  in  groups  of  19  or  less,  extending  across  the 
waterway  to  be  defended,  planted  approximately  100  feet 
apart  and  anchored  so  as  to  have  a  submergence  of  about  10 
feet  at  low  water.     The  groups  are  numbered  1,  2,  3,  etc., 
from  left  to  right  of  the  observer  stationed  in  rear  of  the 
line,  and  the  mines  in  each  group  are  numbered  similarly, 
No.  1  being  on  the  left,  No.  10  in  the  center,  and  No.  19  on 
the  right. 


10  SUBMARINE   MINING. 

The  groups  composing  a  line  of  buoyant  mines  are  not 
usually  planted  in  prolongation  of  each  other,  but  with  a 
space  for  the  passage  of  friendly  vessels,  and  also  for  the 
movement  of  the  planter  when  at  work  upon  adjacent 
groups.  Groups  of  ground  mines  may  be  placed  in  prolon- 
gation of  each  other  or  between  the  groups  of  buoyant  mines, 
as  they  will  always  be  below  the  hulls  of  passing  vessels. 

5.  The  mine  planters  and  other  boats  with  the  necessary 
equipment  for  planting  and  maintaining  the  planted  mines. 

6.  The  range-finding1  system,  the  same  as  or  similar  to  that 
used  for  the  guns,  enabling  accurate  plotting  of  the  positions 
of  the  individual  mines,  and  consequently  permitting  vessel 
tracking  and  observation  firing. 

7.  The  searchlights,   for  illuminating  the   mine   fields   at 
night. 

8.  The  rapid-fire  guns,  for  the  protection  of  the  mine  fields. 


CHAPTER  II. 
MATERIEL  OF  THE  SYSTEM. 

The  generating  set. — This  consists  of  a  D.  C.,  shunt-wound 
generator  driven  by  a  kerosene  oil  engine,  or  of  a  direct - 
connected  gasoline  set.  (For  method  of  operation  of  a 
Hornsby-Akroyd  oil  engine,  see  Appendix  2.) 

The  storage  battery. — This  is  a  40-cell  chloride  accumulator, 
with  a  normal  charge  and  discharge  rate  of  5  amperes.  The 
voltage  may  be  taken  at  2  volts  per  cell ;  the  internal  resist- 
ance is  negligible.  Directions  for  setting  up,  care,  and 
usage  of  the  storage  battery  are  given  in  Appendix  3.  The 
5-ampere  battery  is  the  standard  equipment  at  the  present 
time,  but  the  new  installations  will  have  batteries  with  a 
normal  charge  and  discharge  rate  of  15  amperes. 

The  motor-generator,  D.  C.-A.  C.— This  is  a  D.  C.-A.  C.  (60- 
cycle,  'single  phase)  machine,  running  on  D.  C.  voltage 
(80-110)  and  designed  to  give  one-half  kilowatt  at  80  volts. 
To  insure  against  breakdown  two  of  these  motor  generators 
are  supplied  to  each  casemate. 

Starting  switch. — This  is  a  4-point  lever  switch  and  is  used 
to  start  the  motor-generator  and  to  accelerate  it  to  full  speed. 
To  insure  against  breakdown  two  of  these  motor-generators 
cuit  to  the  fourth -point.  Resistances  are  connected  between 
the  points,  as  shown  in  figure  1.  The  contact  made  at  point  1 
is  not  broken  as  the  lever  is  moved  to  its  successive  positions. 
It  is  seen  that  the  total  resistance  is  8  ohms;  it  is  all  in  the 
armature  circuit  when  the  switch  blade  is  in  the  first  point; 
4  ohms  when  in  the  second  point;  2  ohms  when  in  the  third 
point;  none  when  in  the  fourth  point.  The  operation  of 
closing  the  lever  short  circuits  in  turn  the  resistances  4,  2, 
and  2. 

11 


12 


SUBMARINE   MINING. 


The  casemate  transformer. — This  is  a  step-up  transformer, 
of  the  oil-insulated  core  type,  and  is  rated  at  60  cycles,  500 
watts,  80  volts  primary  and  500  volts  secondary,  when  carry- 
ing full  load. 


Line 

FIG.  1. — Starting  switch. 

The  power  panel. — This  panel  is  shown  in  figure  2,  its  wir- 
ing diagram  in  figure  18  at  the  end  of  the  book.  It  consists 
of  an  enameled  slate  panel  upon  which  the  apparatus  is 
mounted.  It  is  32  inches  wide,  69  inches  high,  and  is  set  up 
with  its  face  34  inches  from  the  wall  in  rear. 


\ 


FIG.  2.— POWER   PANEL. 


SUBMARINE    MINING.  13 

Across  the  top  are  two  lamps,  a  double  circuit  breaker,  a 
D.  P.  D.  T.  switch,  and  a  single  circuit  breaker.  Below  these 
there  are  an  ammeter,  an  A.  C.  voltmeter,  and  a  D.  C.  volt- 
meter. Below  the  ammeter  is  a  battery  rheostat  and  below 
the  D.  C.  voltmeter  a  field  rheostat.  On  a  bracket  at  the  side 
there  is  a  mil-ammeter,  with  a  16  c.  p.,  110- volt  lamp  in  series 
with  it. 

The  remaining  switches,  receptacles,  and  attachments  are 
sufficiently  well  indicated  in  the  figures. 

Switch  No.  1  controls  the  lamps  at  the  top  of  the  board. 
When  it  is  up,  they  are  supplied  from  an  external  source  of 
power.  When  it  is  down,  they  are  supplied  from  the  stor- 
age battery. 

The  D.  C.  terminals  are  all  carried  to  one  terminal  bar, 
the  A.  C.  terminals  to  another.  All  terminals  and  all  switches 
are  labeled. 

Provision  is  made  for  energizing  the  D.  C.  busses : 

(a)  From  an  external  source  of  power :  Close  single  circuit 
breaker  and  close  switch  No.  2  to  the  right — facing  the  board. 

(b)  From    the   casemate  generator:  Close  single   circuit 
breaker  and  close  switch  No.  2  to  the  left — facing  the  board. 

(c)  From  the  storage  battery:  With  switch  No.  2  open, 
close  double  circuit  breaker. 

Feeder  switches  are  plainly  marked.  The  D.  C.  switches 
supply  powrer  as  follows : 

No.  3.  When  up,  supplies  the  operating  boards  (negative 
pole  to  boards,  positive  to  earth)  ;  when  down,  it  is  spare. 

No.  4.  When  up,  supplies  motor-generator  No.  1 ;  when 
down,  motor-generator  No.  2. 

No.  5.  When  up,  supplies  the  mine  commander's  station.  ' 

No.  6.  When  up,  supplies  casemate  lamps;  when  down,  it 
does  the  same,  but  the  power  is  now  drawn  from  an  external 
source  and  not  from  the  D.  C.  busses. 

No.  7.  When  up,  grounds  the  positive  bus  and  connects  the 
negative  bus  through  the  protective  lamp  and  mil- ammeter 
to  the  mil-ammeter  lead. 

The  A.  C.  switches  supply  power  as  follows : 

No.  8.  When  up,  supplies  the  operating  boards,  one  pole 
to  boards,  the  other  to  earth  through  an  independent  lead; 


14  SUBMARINE   MINING. 

when  down,  it  does  the  same,  but  the  side  grounded  is 
grounded  through  a  choke  coil. 

No.  9.  When  up,  energizes  the  A.  C.  busses  from  motor- 
generator  No.  1 ;  when  down,  the  A.  C.  busses  from  motor- 
generator  No.  2. 

No.  10  is  spare. 

No.  11.  When  up,  supplies  power  to  the  primary  of  the 
testing  transformer;  when  down,  it  is  spare. 

No.  12.  When  up,  supplies  power  from  the  secondary  of 
the  testing  transformer  to  the  test  fuses. 

Voltmeter  receptacles  and  plugs,  all  of  which  are  properly 
marked,  are  provided  for  obtaining  the  reading  of  the  A.  C. 
and  D.  C.  voltages.  The  D.  C.  receptacles  are  on  the  right 
and  the  A.  C.  on  the  left.  The  first  receptacle  of  each  set  is 
spare  to  hold  the  plugs  when  the  latter  are  not  in  use. 

With  the  D.  C.  plug: 

In  the  second  receptacle,  the  voltage  of  the  casemate  gen- 
erator is  indicated. 

In  the  third  receptacle,  voltage  of  external  D.  C.  power.  * 

In  the  fourth  receptacle,  voltage  of  storage  battery. 

With  the  A.  C.  plug: 

In  the  second  receptacle,  voltage  of  A.  C.  power  on  the 
busses  is  indicated. 

In  the  third  receptacle,  voltage  of  external  A.  C.  power, 
if  the  latter  is  supplied. 

In  general,  no  external  A.  C.  power  should  be  led  into  the 
casemate,  as  the  system  would  be  unsafe,  owing  to  the  lia- 
bility of  a  "  cross."  The  standard  system  is  perfectly  safe, 
as  it  is  impossible  for  a  mine  to  be  fired  when  the  motor 
generators  are  idle. 

The  double  circuit  breaker  is  an  ordinary  single-coil 
breaker.  The  single  circuit  breaker  is  an  overload  and 
reverse-current  circuit  breaker.  The  reverse-current  coil  has 
two  windings,  one  of  which  is  bridged  across  the  power 
supply,  and  the  other  is  in  series  with  it.  On  charge,  the 
effect  of  these  coils  is  differential,  and  on  discharge  it  is 
cumulative  and  will  trip  the  circuit  breaker  when  the  current 
from  the  storage  battery  exceeds  2  amperes. 


•f        - 


ffiUMllr 

&&>&& 


FIG.  3.— OPERATING   BOARD. 


SUBMARINE    MINING.  15 

To  charge  the  storage  battery: 

(a)  From  an  external  source  of  power:  Both  the  single  and 
the  double  circuit  breakers  are  closed  and  switch  No.  2  is 
closed  to  the  right  (facing  the  board). 

(b)  From  the  casemate  generator:  Both  circuit  breakers 
are  closed  and  switch  No.  2  is  closed  to  the  left  (facing  the 
board). 

The  operating  board. — A  front  view  of  this  is  given  in  figure 
3,  its  wiring  diagram  in  figure  18  at  the  end  of  the  book. 
One  is  required  for  each  group  of  19  mines.  It  consists  of 
an  iron  frame  to  which  are  attached  a  signal  block,  a  master 
block,  19  mine  blocks  (1  for  each  mine),  busses,  and  a  ter- 
minal bar  with  19  numbered  terminals.  The  frame  is  78 
inches  high  by  24  inches  wide.  It  should  be  set  up  so  that 
its  face  is  34  inches  from  the  wall  in  rear. 

The  signal  block  (see  fig.  18). — This  is  an  enameled  slate 
block  24  inches  wide  and  11  inches  high,  upon  which  are 
mounted  three  binding  posts,  three  lamps  (red,  white,  and 
green),  a  bell  and  bell  switch,  a  90-ohm  noninductive  resist- 
ance in  parallel  with  the  white  lamp,  and  a  125-ohm  re- 
sistance in  series  with  the  bell.  The  binding  posts  are 
marked  "  Earth  "  or  "  G.,"  "A.  C.,"  and  «  D.  C.,"  respectively. 
The  bell,  the  90-ohm  non-inductive  resistance,  and  the  125- 
ohm  resistance  are  so  indicated  on  the  figure.  The  lamps  are 
marked  as  follows:  Red,  "  R.  L.";  white,  "W.  L.";  green, 
"  G.  L." 

The  circuit,  under  normal  conditions,  is:  From  negative 
D.  C.  bus  on  power  panel,  to  switch  3  closed  up,  to  "  oper- 
ating board  "  terminal,  to  D.  C.  lead,  to  D.  C.  post  on  signal 
block,  through  green  lamp,  to  D.  C.  jaw  on  master  block,  to 
D.  C.  bus  on  operating  board,  through  power  switch  P  on 
mine  block,  through  solenoid  S,  to  middle  of  testing  switch 
T,  to  upper  contact  of  same,  to  upper  contact  of  automatic 
switch  A,  to  middle  of  same,  to  mine  switch  M,  through 
same  to  terminal  bar,  through  19-conductor  and  single-con- 
ductor cables,  through  mine  transformer  primary,  to  mine 
case,  to  ground,  to  D.  C.  "  earth  "  terminal  on  power  panel,  to 
switch  3,  and  to  positive  D.  C.  bus  on  power  panel. 


16  SUBMARINE    MINING. 

Green  lamps  of  8,  1C,  and  32  candlepower  are  supplied. 
The  16-candlepower  green  lamp  glows  dimly  when  19  mines 
are  connected  to  the  operating  board  and  all  are  free  from 
short  circuits,  grounds,  or  abnormal  resistances.  If  it  should 
glow  abnormally  bright,  due  to  grounds,  a  32-candlepower 
lamp  should  be  substituted.  If  it  should  glow  very  dimly, 
due  to  a  less  number  of  mines  connected,  an  8-candlepower 
lamp  should  be  used. 

A  short  circuit  in  a  mine  circuit  causes  the  green  lamp  to 
glow  more  brightly. 

Breaks  in  conductors  not  causing  short  circuits  will  not  be 
revealed  ordinarily  by  this  lamp.  To  detect  breaks,  tests  of 
individual  mines  must  be  made. 

The  red  lamp  glows  and  the  bell  rings  when  any  automatic 
switch  is  down.  The  circuit  under  this  condition  is: 

From  negative  D.  C.  bus  on  power  panel  to  switch  3 
closed  up,  to  "  operating  board  "  terminal,  to  D.  C.  lead,  to 
D.  C.  post  on  signal  block,  through  green  lamp  to  D.  C.  jaw, 
to  D.  C.  operating  board  bus,  through  power  switch  on  mine 
block  whose  automatic  switch  is  down,  through  insulated 
pin  of  lower  arm  of  automatic  switch,  to  lower  point  of 
testing  switch  T,  to  operating  board  lamp  bus,  through  bell. 
125-ohm  resistance  and  bell  switch,  and  red  lamp  in  parallel, 
to  "  earth  "  post,  to  earth  lead^  to  D.  C.  "  earth  "  terminal  on 
power  panel,  to  switch  3,  and  to  positive  D.  C.  bus  on  power 
panel. 

The  resistance  of  the  bell  is  such  that  a  resistance  of  125 
ohms  must  be  placed  in  series  with  it  to  make  the  joint  re- 
sistance of  the  red  lamp-bell  circuit  so  large  that  if  one  auto- 
matic switch  is  down  it  will  not  interfere  with  the  tripping 
of  another. 

The  white  lamp,  W.  L.,  is  in  the  firing  and  A.  C.  testing 
circuits.  The  90-ohm  resistance  is  in  parallel  with  this  lamp, 
and  in  addition  to  protecting  it  from  excessive  current,  serves 
to  keep  the  firing  circuit  complete  should  the  lamp  burn  out. 

The  master  block  (see  fig.  18). — This  is  an  enameled  slate 
block  6  inches  wide  by  9J  inches  high,  upon  which  are 
mounted  two  jaws  for  the  terminals  of  a  jumper,  a  testing 
switch,  T.  S.,  and  a  firing  switch,  F.  S. 


11003° — 12 2 


r -Automatic  Switch 


..Mine  Switch 


Automatic  Switch 
Release 


Power  Switch 


Solenoid 


'L— -  Testing  Switch         *L — Solenoid  Plunger 

FIG.  4.— MINE  BLOCK. 


SUBMARINE    MINING.  17 

The  testing  switch,  T.  S.,  is  used  to  determine  if  the  A.  C. 
power  be  on  the  signal  block.  If  so,  when  it  is  closed  the 
white  lamp  on  signal  block  glows.  This  switch  is  marked 
to  indicate  its  "  off  "  and  "  on  "  positions.  When  "  on  "  the 
circuit  is  as  given  in  "  test  of  the  delivery  of  the  A.  C.  power 
to  the  operating  board,"  Chapter  VI. 

The  firing  switch,  F.  S.,  is  used  to  throw  the  A.  C.  power 
on  the  operating  board  A.  C.  busses.  This  is  marked  to  show 
its  "  on  "  and  "  off  "  positions.  No  mine  can  be  fired  unless 
this  switch  is  in  its  "  on  "  position.  When  "  on  "  the  firing 
circuit  is  as  follows: 

From  A.  C.  bus  on  power  panel  to  switch  8  closed  up,  to 
"  operating  board  "  terminal,  to  A.  C.  lead,  to  A.  C.  post  on 
signal  block,  to  white  lamp  and  resistance  in  parallel,  to 
A.  C.  jaw,  through  firing  switch,  F.  S.,  to  A.  C.  b,us  on 
operating  board,  to  lower  point  of  automatic  switch  when  it 
is  closed  down,  to  middle  point  of  automatic  switch,  through 
mine  switch  to  terminal  bar,  through  19-conductor  and 
single-conductor  cables,  through  mine  transformer  primary, 
to  mine  case,  to  ground,  to  A.  C.  "earth  "  terminal  on  power 
panel,  to  switch  8.  and  to  other  A.  C.  bus  on  power  panel. 
The  white  lamp  glows  after  the  mine  has  been  fired. 

The  mine  block  (see  figs.  4  and  18). — This  consists  of  an 
enameled  slate  block,  6  inches  wide  and  9J  inches  high,  on 
which  are  mounted  four  switches. 

1.  The  upper  switch  is  the  "  mine  switch."     When  it  is 
open  the  corresponding  mine  is  cut  out  and  can  not  be  fired. 
It  is  placed  horizontally  on  the  blocks  of  the  old  model  and 
vertically  on  those  of  the  new  model. 

2.  The  right-hand  switch,  a  S.  P.  S.  T.  knife  switch,  is 
the  "power  switch."     When  it  is  closed  the  D.  C.  power  is 
on  the  block  and  the  automatic  switch  will  function  when 
the  corresponding  mine  is  struck.     When  it  is  .open  the  mine 
can  be  fired  by  raising  the  automatic  switch  release,  thus 
tripping  the  automatic  switch. 

3.  The  central  switch  is  the  "  automatic  switch,"  a  single- 
pole  double-throw  switch,  operated  by  the  plunger  of  a  sole- 
noid.    Through  its  lower  arm  there  passes  an  insulated  pin 


18  SUBMARINE    MINING. 

which,  when  the  switch  is  down,  makes  connection  between 
two  contacts  to  the  right  and  left  of  this  arm. 

If  for  any  cause  the  current  through  the  solenoid  rises 
above  that  for  which  it  is  set  (normally  0.075  ampere),  its 
plunger  is  drawn  up  and  the  switch  is  tripped.  Such  rise  in 
current  is  produced  when  a  mine  is  struck,  the  resistance 
through  the  circuit-closer  circuit  being  far  less  than  that 
through  the  primary  coil  of  the  transformer.  Such  would 
also  be  the  case  when  a  mine  cable  is  grounded. 

When  the  automatic  switch  is  tripped,  the  D.  C.  circuit  to 
the  mine  is  broken  at  its  upper  contact  (see  fig.  18)  and  D.  C. 
circuit  through  red  lamp  and  bell  is  made  through  the  insu- 
lated through  pin  in  the  lower  arm,  thus  giving  warning. 
If  at  the  same  time  A,  C.  power  be  on  the  busses  and  the 
firing  switch  on  the  master  block  be  closed,  A.  C.  will  be 
thrown  on  the  mine  through  the  lower  contact  of  the  auto- 
matic switch,  and  the  mine  will  be  fired. 

Just  above  the  plunger  of  the  solenoid  there  is  a  red  knob 
attached  to  the  tripping  bar  of  the  automatic  switch  release. 
This  enables  the  automatic  switch  to  be  released  by  hand  in 
observation  firing  and  in  testing. 

4.  The  left-hand  switch,  a  S.  P.  D.  T.  switch,  is  the  "  test- 
ing switch."  It  is  used  to  test  the  automatic  switch,  which 
should  open  when  the  testing  switch  is  thrown  down.  The 
bell  switch  should  be  opened  before  throwing  down  testing 
switch.  When  the  testing  switch  is  in  this  position,  the  cir- 
cuit being  broken  at  its  upper  contact,  the  mine  is  cut  out, 
and  in  place  of  the  mine  there  is  thrown  in  the  red  lamp  of 
the  signal  block.  The  resistance  of  this  red  lamp  is  greater 
than  that  of  the  mine  circuit  when  the  mine  is  struck,  so  that 
if  the  automatic  switch  works  for  the  current  through  the 
red  lamp  it  will  certainly  work  for  that  through  the  circuit 
closer  when  the  mine  is  struck. 

The  circuit  when  the  testing  switch,  T,  is  down  and  before 
the  automatic  switch  drops  is :  From  negative  D.  C.  bus  on 
power  panel,  to  switch  3  closed  up,  to  "  operating  board  " 
terminal,  to  D.  C.  lead,  to  D.  C.  post  on  signal  block,  through 
green  lamp,  to  D.  C.  jaw,  to  D.  C.  bus  on  operating  board, 
through  power  switch,  through  solenoid  to  middle  of  testing 


SUBMARINE    MINING.  19 

switch  T,  to  lower  point  of  same,  to  operating  board  lamp 
bus  L,  through  red  lamp  to  "  earth  "  post,  to  earth  lead,  to 
D.  C.  "  earth  "  terminal  on  power  panel,  to  switch  3,  and  to 
positive  D.  C.  bus  on  power  panel.  The  circuit,  when  testing 
switch,  T,  is  down,  and  after  the  automatic  switch  has  dropped, 
is  the  same  as  the  above  up  to  the  power  switch,  then  from 
the  power  switch  through  the  insulated  pin  in  the  lower 
part  of  the  automatic  switch,  to  the  lower  jaw  of  the  testing 
switch,  and  then  the  same  as  the  circuit  above. 

A  diagram  similar  to  the  wiring  diagram,  figure  18,  at  the 
end  of  the  book  should  be  made  of  the  power  panel  and  of 
one  of  the  operating  boards  of  each  casemate  and  posted  in  a 
conspicuous  place  in  the  casemate.  Any  changes  made  in  the 
wiring  of  either  of  these  boards  should  be  made  immediately 
on  this  diagram. 

Submarine  mine  cable,  19-conductor. — This  is  an  armored 
cable  about  1  inch  in  diameter  and  contains  19  insulated 
single  conductors  of  No.  16  American  wire  gauge  wire  (51 
mils  in  dia.) .  The  conductors  are  arranged  in  two  concentric 
layers  around  a  single  central  conductor,  the  inner  layer  con- 
taining 6,  the  outer  12.  One  conductor  in  each  layer  is  dis- 
tinguished from  the  rest  by  some  characteristic  mark,  as  a 
spiral  white  thread,  a  wrapping  of  tape,  or  other  easily  de- 
tected mark.  The  marked  conductor  in  the  outer  layer  is 
No.  1,  that  in  the  inner  layer  No.  13,  and  the  central  con- 
ductor is  No.  19.  The  other  conductors  are  numbered  at  the 
shore  end  of  the  cable  in  a  clockwise  direction ;  at  the  distant 
end  in  a  contraclockwise  direction. 

Submarine  mine  cable,  7-conductor. — In  many  cases  the  7- 
conductor  cable  now  on  hand  can  be  used  to  advantage  for 
mine  work,  particularly  in  planting  groups  which  do  not 
require  great  lengths  of  multiple  cable.  In  all  such  cases 
the  old  grand  junction  boxes  are  to  be  used  as  distribution 
boxes,  thus  providing  for  separate  groups  of  7  mines. 

Submarine  mine  cable,  single  conductor. — This  is  an  armored 
cable,  about  three-fourths  inch  in  diameter,  and  contains 
an  insulated  conductor  made  of  7  strands  of  soft  annealed 
No.  22  American  wire  gauge  copper  wire  (25.35  mils  in  dia.). 


20  SUBMARINE    MIXING. 

The  buoyant-mine  case. — The  service  32-inch,  pattern  is 
made  of  10-pound,  ^-inch,  open-hearth  steel,  of  great  tough- 
ness and  elasticity,  and  is  thoroughly  galvanized.  The  shell 
consists  of  two  hemispheres,  ribbed  and  welded  together  at 
the  equator,  thus  avoiding  all  rivets.  Every  case  before  it  is 
accepted  is  tested  with  an  internal  hydraulic  pressure  of  100 
pounds  per  square  inch. 

The  top  hemisphere  is  provided  with  an  external  man- 
euvering ring ;  the  bottom  hemisphere  has  a  hole  5^  inches 
in  diameter  at  the  pole.  The  edge  of  the  hole  is  reenforced 
by  a  welded  ring  1^  inches  thick ;  and  near  it  are  four  bosses, 
also  welded,  carrying  screw  bolts  which  project  2^  inches 
outside  to  secure  the  cap. 

The  cap  consists  of  a  hemisphere  of  15-pound,  f-inch 
wrought  iron,  flanged  and  dished  at  the  base  to  fit  the  case, 
to  which  it  is  attached  by  the  four  bolts  already  mentioned. 
They  pass  through  slots  in  the  flange,  which  is  then  held  in 
place  by  shoes  and  nuts  which  are  keyed  on.  The  water  has 
free  access  to  the  chamber  inside  the  cap.  The  uses  of  the 
cap  are:  To  clamp  the  Turk's-head  of  the  mine  cable,  to 
cover  and  protect  the  portion  of  the  core  exposed  outside  the 
case,  and  to  serve  as  an  attachment  for  the  wire  mooring 
rope. 

A  hole  1-J  inches  in  diameter  at  the  pole  of  the  cap  is  con- 
nected by  means  of  a  slot  with  a  3-inch  hole  punched  through 
the  cap  between  two  of  the  bails.  This  arrangement  per- 
mits the  entrance  or  removal  of  the  Turk's-head  without  re- 
moving the  cap  from  the  mine  case.  The  mooring  attach- 
ment consists  of  a  ring  of  IJ-inch  wrought  iron,  having  a 
hole  2^  inches  in  diameter,  attached  to  the  cap  by  three  bails 
of  1-inch  wrought  iron  permanently  double  riveted  to  the 
sides.  The  cap  is  thoroughly  galvanized. 

The  large  hole  in  the  mine  case  covered  by  the  cap  is  closed 
by  a  plug.  The  joint  is  made  water  tight  by  a  lead  washer 
jammed  between  the  plug  proper  and  the  case  and  by  a  coat- 
ing of  red  lead  or  similar  waterproofing  material  upon  the 
screw  threads.  In  the  strong  currents  and  deep  water  of 
some  harbors  more  buoyancy  than  is  possessed  by  the  32-inch 
case  is  required.  This  is  obtained  by  inserting  between  the 


Cop 

Circuit  C/oser 
Springs 


P/ate 

D/3  tan  ce    R/ng 
Bo// 


r?eocfanc&  Terminal 


Transformer- 


Primary    Term/no/ 
Screw 


Fuse  Con 


Trofo/ 


fuse  Can  Cap 
Jef  Screw 
Lower 

Set  Screw 
P/vg  Proper 
Rubber  Packing 


Bo//   Sear 
-Primary    Term/no/ 


Reinforce 
Lead  Washer 
Brass  G/ond 


Lead  Washers 


Brass  G/and 


Loading  W/re 


FIG.  5.— COMPOUND   PLUG,  OLD  MODIEL  FUSE  CAN. 


Cop 

C/rcvf  C/oser- 
Ba// 


Trans  for  me  r 
Reactance 


P/ore 


Primary  Co//- 


Co//ar. 
Cotter  Pin 


Bo/f  Securing 


Screws 

Conn&cfing  Co//or 
Okonite  and  Hanson 
Tape 


Brass  Jointers 


Connecting   Bolt 
Rubber 


Dry 

Oun  Co  f  ton 
Primer  Cokes 


Rubber  Pocking 

h» 

Proper* 


FIG.  6— COMPOUND   PLUG,   RUBBER   FUSE  CAN. 


Cop 


Circuit  C/oser- 
Ball  Seat 


Transformer- 
fteacfance 

Pr/mory  Co//- 
Brass  Co//ar 
Colter  P/'n 


Plate 
Distanc  e    Ring 


—  Bo/t  Securing 
Nuts 

Connecting  Collar 
Connecting  0o/t 


Fuse  Con 


Fuses 


Brass  Washer 
Lead  Washer- 


fuse  Can   Cap 
I — Rubber  Pocking 


~^p-  Plug ,  Proper 
Rubber  Packing 
Brass    Gfand 


4-  o  a  a*  ing 


Wire 


FIG.  7.— COMPOUND   PLUG,  TROTOL  FUSE  CAN. 


SUBMAKIKE    MINING. 


21 


hemispheres  a  cylinder  of  20-pound  wrought  iron  which  is 
stiffened  by  extra  welded  ribs  for  the  larger  sizes.  Such  cases 
are  designated  by  the  diameter  in  inches  of  a  sphere  having 
the  same  buoyancy.  Thus,  a  Xo.  40  case  is  made  by  inserting 
a  cylinder  32  inches  in  diameter  and  20.4  inches  in  length 
between  the  two  hemispheres  of  a  No.  32  case;  this  is  suffi- 
cient to  make  the  displacement  equal  to  that  of  a  spherical 
case  40  inches  in  diameter.  In  the  latest  types  the  cylinders 
are  made  of  corrugated  mild  steel  of  less  thickness,  which 
diminishes  very  materially  the  weights  of  the  cases. 

The  following  table  exhibits  the  dimensions  and  weights 
of  buoyant  mines,  with  trot  pi  fuse  cans,  complete  except  the 
charges  and  moorings.  The  actual  free  buoyancy  when 
planted  will  be  the  difference  between  the  displacement  and 
weight  as  given  in  the  table,  reduced  by  the  weight  of  the 
charge  and  of  the  moorings  and  cables : 


PLAIN  CASES. 


No. 

Dis- 
place- 
ment. 

Com- 
puted 
weight, 
empty. 

Meas- 
ured 
weight, 
empty. 

Length 
of 
cylinder. 

Remarks. 

32 

33 

Pounds, 
635 

695 

Pounds. 
308 

364 

Pounds. 
311 

Feet. 
0.00 

.17 

All  are  about  33J  inches  in  outside  diameter; 
the  extreme  length  in  each  case  is  4.3  feet 
plus  the  length  of  the  cylinder. 

34 

762 

395 

.35 

35 

829 

427 

.54 

36 

904 

462 

.75 

i 

37 

982 

498 

.96 

38 

1,064 

538 

1.20 

39 

1,149 

578 

1.43 

40 
41 

1,242 
1,341 

621 
665 

(525 

1.70 
1.96 

4*> 

1,436 

712 

2.24 

43 
44 

1,540 
1,652 

788 
842 

759 

2.53 
2.77 

One  extra  welded  rib. 

45 

1  767 

876 

3.17 

Do 

46 

47 
43 

1,887 

2,013 
2,144 

952 

1,011 
1,073 

f          899 
\          936 

~"i,"637' 

|        3.50 

3.85 
4.20 

/Lot  of  1879;  one  extra  welded  rib. 
\Lot  of  1884;  one  extra  welded  rib. 
One  extra  welded  rib. 
Do. 

CORRUGATED  CASES. 


47 

1,536 

572 

2.24 

V) 

2,323.2 

777 

4.22 

The  compound  plug,  with  old  model  brass  fuse  can. — A  sec- 
tion of  this  plug,  with  the  names  of  all  the  parts,  is  shown 


22  SUBMARINE    MINING. 

in  figure  5.  The  brass  fuse  can  is  not  used  when  guncotton 
is  used  as  a  priming  charge. 

The  compound  plug,  with  rubber  fuse  can. — A  section  of  this 
plug,  with  the  names  of  all  the  parts,  is  shown  in  figure  6. 

The  compound  plug,  with  trotol  fuse  can. — A  section  of  this 
plug,  with  the  names  of  all  the  parts,  is  shown  in  figure  7. 

In  each  plug  the  main  parts  are  screwed  together  and  held 
in  place  by  set  screws.  The  connection  of  the  compound 
plug  with  the  mine  case  makes  an  earth  plate,  of  which  the 
electrical  resistance  in  salt  water  is  about  1  ohm. 

The  mine  transformer  (see  fig.  8). — This  consists  of  a  cylin- 
drical brass  case,  which  contains  the  primary  and  secondary 
coils  of  the  transformer  and  the  reactance  coil.  The  trans- 
former is  screwed  into  the  brass  collar  or  the  reenforce  and 
in  turn  has  the  circuit  closer  screwed  upon  its  top.  The 
fuses  are  attached  to  the  secondary  and  are  fired  when  proper 
voltage  is  applied  to  the  primary.  The  primary  leads  are 
black;  those  of  the  secondary  are  red.  The  terminal,  P',  of 
the  primary  coil  is  left  free  for  the  purpose  of  testing,  but 
when  preparing  the  transformer  for  use  it  is  attached 
securely  to  the  binding  post,  T.  The  upper  terminal,  R', 
of  the  reactance  is  prepared  for  attachment  to  the  ball  seat 
of  the  circuit  closer. 

The  normal  circuit  is  from  P,  'through  the  primary  coil 
(the  resistance  of  which  is  about  2,400  ohms),  to  the  trans- 
former case,  and  thence  tto  earth.  However,  when  the  mine 
is  struck,  so  as  to  close  the  circuit  closer,  a  parallel  circuit  is 
closed  through  the  reactance  (the  resistance  of  which  is  about 
130  ohms),  thence  to  the  ball  seat  of  the  circuit  closer, 
through  the  ball  and  springs  to  the  transformer  case,  and 
thence  to  earth.  In  this  latter  case,  therefore,  the  resistance 
is  lessened  by  about  2,300  ohms. 

The  reactance  coil  will  permit  only  a  small  amount  of 
alternating  current  to  pass  through  it  when  the  ball  is  dis- 
placed, hence  mines  may  be  fired  whether  the  ball  is  displaced 
or  not. 

Two  fuses  are  connected  in  multiple  across  the  ends  of 
the  secondary  terminals.  These  terminals  are  10  inches  in 


REACTANCE: 


PRIMARY  COIL 


SECONDARY 
COIL 


FIG.  8.— MINE  TRANSFORMER. 


SUBMAKINE    MINING.  23 

length,  to  allow  ample  margin  for  inserting  fuses  in  the 
primer. 

The  transformer  is  of  the  step-down  type  and  is  rated  at 
22.5  watts,  60  cycles,  500  volts  primary,  and  14  volts  sec- 
ondary. 

The  mine  circuit  when  normal  is  such  that  80  volts  should 
give  only  30  mil-amperes,  but  a  mine  may  be  fired  even  when 
the  circuit  is  so  defective  that  80  volts  give  120  mil-amperes. 

Furthermore,  150  volts  D.  C.  may  be  applied  to  the  pri- 
mary without  danger  of  explosion. 

An  explosion  can  not  be  produced  unless  the  A.  C.  busses 
on  the  operating  board  are  energized,  and  as  long  as  the 
firing  switch  on  the  master  block  is  open,  there  is  no  danger 
from  accidental  closing  of  switches  in  making  mine  tests  or 
from  short  circuits  in  the  mine. 

NOTE. — In  designing  this  transformer  the  following  varia- 
tions were  considered:  (a)  Omitting  reactance  and  tapping 
to  ball  seat  beyond  primary  of  transformer;  (b)  using  a 
condenser;  (c)  using  two  sets  of  fuses,  so  as  to  be  able  to  fire 
with  either  D.  C.  or  A.  C.  All  were  eliminated,  as  they 
impaired  either  the  safety,  the  simplicity,  or  the  efficiency  of 
the  system. 

The  circuit  closer. — This,  when  used  with  the  buoyant  mine, 
consists  of  the  following  parts:  The  cap,  the  spring  plate, 
the  distance  ring,  the  steel  ball,  and  the  ball  seat,  which,  when 
assembled,  are  mounted  on  the  top  of  the  mine  transformer. 

The  ground-mine  case. — The  form  and  details  of  construc- 
tion adopted  for  the  service  pattern  are  the  following  (see 
fig.  9)  :  The  case  is  cast  iron,  in  form  a  segment  of  a  sphere, 
of  which  the  height  is  two-thirds  of  the  radius.  The  bottom 
is  nearly  flat,  wyith  a  central  sand-hole  plug  to  empty  the 
casting.  Six  internal  radial  ribs  are  added  to  give  addi- 
tional supports  to  the  top;  the  loading  hole,  5J  inches  in 
diameter  (3  inches  in  old  pattern),  is  at  the  pole  and  is 
closed  by  a  compound  plug.  Before  acceptance  a  hydraulic 
pressure  of  100  pounds  per  square  inch  must  be  borne  with- 
out developing  leakage. 


24 


SUBMARINE    MINING. 


Only  one  size  of  ground  mine  has  been  introduced  into 
our  service.  This  pattern  is  designed  to  contain  from  200 
to  300  pounds  of  explosive  and  to  rest  on  the  bottom  in  water 
not  exceeding  35  feet  in  depth  at  high  tide.  The  dimensions 
are  as  follows:  Radius  of  the  sphere,  21^  inches;  diameter 
of  the  base,  40  inches;  extreme  height,  25  inches;  thickness 
of  iron,  seven-tenths  of  an  inch;  weight,  empty  in  the  air, 
1,355  pounds;  when  submerged  it  loses  515  pounds.  The 
capacity  of  this  case  is  about  5  cubic  feet. 

A  mine  cap  is  provided  to  clamp  the  Turk's-head  of  the 
mine  cable,  to  cover  and  protect  the  portion  of  the  core 


CAP 
GLAND  — 


FUSE  CAN 


FIG.  9. — Ground-mine  case. 

exposed  outside  the  case,  and  to  serve  as  an  attachment  for 
the  mooring  and  the  raising  ropes.  This  cap  is  held  to  the 
mine  case  by  six  bolts,  and  is  fitted  with  two  rings,  one  for 
attachment  of  the  mooring  rope  of  the  circuit-closer  buoy 
and  the  other  for  attachment  of  the  raising  rope. 

The  compound  plug,  ground  mine. — This  is  similar  to  the 
compound  plug  for  buoyant  mines.  The  circuit  closer  is 
placed  in  a  buoy  above  the  mine. 

The  mushroom  anchor. — The  1,000-pound  anchor  is  in  shape 
a  right  cylinder  about  10  inches  in  height  and  26  inches  in 
diameter,  slightly  dished  on  the  bottom  to  increase  the  hold- 


11003° — 12 3 


FIG.  10a.— AUTOMATIC  ANCHOR. 


SUBMARINE   MINING.  25 

ing  power  in  mud.  For  a  rock  bottom  six  projecting  toes 
increase  the  holding  power;  corresponding  depressions  on 
the  top  permit  piling  when  in  store.  The  heavy  anchors, 
2,000  and  3,000  pounds,  are  of  the  same  form.  The  cylindri- 
cal form  is  adopted  to  facilitate  handling,  since  in  that  shape 
the  anchor  may  be  rolled  readily  on  its  edge. 

The  absolute  stress  of  the  mine  and  its  moorings  upon  a 
mushroom  anchor  of  this  kind  is  easily  computed,  being 
the  square  root  of  the  sum  of  .the  squares  of  the  buoyant 
effort  and  of  the  horizontal  pressure  exerted  by  the  current. 
The  latter,  in  pounds  per  square  foot  of  exposed  cross  sec- 
tion, may  be  estimated  at  one-half  the  square  of  the  velocity 
of  the  current  in  feet  per  second.  A  coefficient  of  safety 
should  cover  the  jerking  effect  of  the  waves  and  the  shocks 
of  friendly  vessels.  It  will,  of  course,  vary  with  the  locality 
and  with  the  absolute  weight  of  the  anchor,  but  in  general  a 
value  from  3  to  5  is  considered  sufficient. 

The  holding  power  of  such  an  anchor  varies  greatly  with 
the  nature  of  the  bottom.  If  this  be  hard,  the  dead  weight 
alone  must  be  depended  upon ;  if  soft,  at  least  double  power 
may  be  anticipated.  In  swift  water  the  buoyant  mine  can 
be  better  held  in  position  by  two  anchors  chained  together. 

The  shackles. — The  wire  mooring  rope  is  attached  to  the 
anchor  and  to  the  case  by  shackles,  of  which  there  are  two 
sizes.  The  anchor  shackle  consists  of  a  wrought-iron  strap 
with  two  eyes  bent  into  the  usual  curved  form  and  offering 
a  thickness  of  \\  inches  at  the  bottom,  where  the  wear  and 
sand  cutting  is  greatest,  and  of  a  IJ-inch  wrought-iron  bolt 
fitted  flush  with  the  outside  of  the  straps.  The  bolt  is  held 
in  position  by  a  split  key,  which,  after  insertion  through  a 
small  hole  in  the  bolt  and  one  of  the  eyes  (in  the  old  model) , 
is  opened  so  that  it  can  not  work  loose. 

The  mine  shackle  is  lighter,  being  1  inch  thick  at  the  bot- 
tom, with  a  1-inch  bolt;  otherwise  it  is  identical  in  pattern 
with  the  anchor  shackle. 

Sister  hooks. — They  are  used  to  connect  the  bail  of  the 
mushroom  anchor  to  the  anchor  shackle.  They  are  of  drop- 
forged  steel  of  high  tensile  strength  and  weigh  about  7 
pounds  per  pair. 


26  SUBMARINE    MINING. 

The  automatic  anchor,  Artillery  type,  1910  (see  figs.  10  a 
and  b). — This  is  a  device  intended  for  use  with  buoyant 
mines,  and  by  means  of  which  such  mines  may  be  anchored 
in  any  depth  of  water,  with  any  desired  depth  of  submerg- 
ence given  automatically. 

The  anchor  is  bell-shaped,  28  inches  in  diameter  at  the 
bottom,  28^  inches  high  over  all,  and  composed  of  the  follow- 
ing parts :  Body,  cover,  reel,  journal-box  caps,  ratchet,  pawl, 
pawl  spring,  distance  rope,  distance  weight,  brakes,  bails, 
necessary  bolts,  wrenches,  and  crank  handles. 

The  pawl  is  drawn  away  from  the  ratchet  by  a  weight  sus- 
pended a  certain  distance  below  the  anchor.  This  is  called 
the  distance  weight,  and  the  submergence  is  regulated  by  the 
distance  this  weight  is  from  the  anchor.  In  falling  through 
the  water  the  mooring  rope  will  unreel  and  the  mine  will 
remain  on  the  surface,  but  wrhen  the  distance  weight  reaches 
the  bottom  the  pawl  spring  forces  the  pawl  into  the  teeth 
of  the  ratchet,  and  as  the  latter  is  attached  to  the  reel  shaft, 
it  prevents  the  reel  from  turning  and  hence  unreeling. 

These  anchors  weigh  approximately  1,500  pounds,  includ- 
ing the  200-pound  distance  weight. 

In  order  to  control  the  speed  of  revolution  of  the  reel, 
the  friction  brakes  must  be  adjusted  properly.  To  do  this, 
a  pull  is  put  on  the  mooring  rope  with  a  spring  balance 
rigged  to  show  the  amount  of  pull ;  the  pull  for  a  particular 
size  of  case  is  determined  by  experiment.  For  a  No.  40  mine 
case  the  adjusting  screws  of  the  brake  shoes  are  regulated 
so  that  the  reel  will  revolve  slowly  when  a  pull  of  300  pounds 
is  registered. 

The  pawl  spring  is  9J  inches  long  and  of  such  strength  that 
a  pull  of  36  pounds  will  extend  the  spring  1J  inches.  The 
pawl-spring  bolt  is  of  such  length  that  the  pawl  spring  will 
be  just  at  the  point  of  tension  when  the  top  of  the  pawl- 
spring  bolt  is  flush  with  the  top  of  the  pawl-spring-bolt  nut 
and  the  pawl  fully  seated  in  the  ratchet. 

When  the  tidal  currents  are  such  as  to  require  a  heavier 
anchor  to  hold  the  mine  than  the  1,500-pound  automatic 
anchor,  the  following  combination  anchor  will  be  used:  At- 
tach a  mushroom  anchor  by  means  of  a  mooring  rope  (about 


FIG.  105.-AUTOMATIC  ANCHOR. 


SUBMARINE   MINING.  27 

8  feet  long)  and  clips  to  the  bail  in  the  bottom  of  the  auto- 
matic anchor.  If  necessary,  two  mushroom  anchors  may  be 
fastened  together  by  bolts  and  these  attached  to  the  auto- 
matic anchor  as  stated  above. 

A  3,000-pound  automatic  anchor,  similar  to  the  1,500- 
pound  automatic  anchor,  is  supplied  for  some  localities. 

The  mooring  sockets. — To  connect  the  wire  mooring  rope  to 
the  shackles  at  the  mine  and  the  anchor,  a  closed  socket  is 
attached  at  each  end.  The  eye  of  the  socket  has  a  clear 
opening,  1T%  inches,  designed  to  receive  the  bolt  of  the 
shackle.  The  end  of  the  rope  is  passed  into  the  socket, 
spread  out,  and  secured  by  pouring  in  a  melted  socket  alloy. 

A  substitute  method  for  connecting  the  wire  mooring  rope 
to  the  shackles  is  to  bend  the  ends  of  the  mooring  rope  by 
means  of  a  small  vise  around  a  galvanized-iron  thimble  and 
fasten  the  end  by  two  bolted  clips. 

Wire  mooring  rope. — This  is  the  highest  grade  of  j-inch 
galvanized-steel  wire  rope,  consisting  of  6  compound  strands, 
each  made  of  19  wires,  the  whole  laid  around  a  steel  center. 
Its  breaking  strength  when  new  is  about  18  tons.  Its  weight 
per  running  foot,  submerged,  is  about  eight-tenths  of  a 
pound.  It  is  used  for  mooring  mines  to  mushroom  anchors. 

Marline-covered  wire  mooring  rope. — For  mooring  mines  to 
the  automatic  anchors  and  for  raising  rope  marline- 
covered  wire  rope  is  used.  This  rope  consists  of  five  outer 
strands  wound  around  a  central  hemp  core.  Each  of  the 
outer  strands  consists  of  a  small  twisted  wire  rope  wound 
around  with  four  strands  of  marline.  One  end  of  the  rope  is 
prepared  for  attachment  to  the  mine  by  passing  it  over  a 
thimble  and  fastening  it  to  the  standing  part  by  means  of 
two  clips.  A  shackle  joins  the  thimble  and  the  bail  of  the 
mine.  The  other  end  of  the  rope  is  made  secure  to  the  reel 
of  the  anchor.  The  breaking  strength  of  ^-inch  marline- 
covered  rope  is  17,000  pounds,  that  of  f-inch  marline-covered 
rope  is  27,000  pounds.  The  weight  per  running  foot  of  the 
|-inch  rope  is  0.5  pound,  that  of  the  f-inch  rope  is  0.8  pound. 
The  weight  of  this  rope  submerged  is  about  60  per  cent  of  its 
weight  in  air. 


28  SUBMARINE   MINING. 

About  155  feet  of  the  £-inch  and  85  feet  of  the  |-inch  mar- 
line-covered rope  can  conveniently  be  wound  on  the  G-inch 
reel  of  the  1,500-pound  automatic  anchor. 

Marline-covered  wire  distance  weight  rope. — For  attaching 
distance  weights  to  the  automatic  anchor  J-inch  marline- 
covered  wire  rope  is  used.  This  rope  is  identical  in  pattern 
with  the  marline-covered  wire  mooring  rope. 

The  distribution  box,  19-conductor. — This  is  a  circular,  cast- 
iron,  disk-shaped  box  which  receives  the  end  of  the  multiple 
cable,  in  which  taped  joints  are  made  between  the  separate 
conductors  of  this  cable  and  the  single-conductor  mine 
cables,  and  from  which  these  mine  cables  radiate.  It  is 
about  27  inches  in  diameter  and  weighs  about  300  pounds. 
It  consists  of  two  parts,  a  bowl-shaped  bottom  6  inches  deep 
inside  and  a  slightly  curved  lid.  The  latter  has  an  iron  ring 
in  its  center  by  which  the  box  is  raised  and  lowered. 

Eight  pins,  fastened  to  the  bottom,  fit  in  corresponding 
holes  in  the  edges  of  the  lid  and  are  slotted  for  keys  by 
which  the  two  parts  are  fastened  together. 

The  vertical  edge  of  the  bottom  is  cut  with  20  slots,  each 
about  2J  inches  deep.  One  of  these  is  larger  than  the  others 
and  receives  the  multiple  cable ;  the  others  are  for  the  single 
conductor  cables.  When  in  use  these  slots  are  numbered 
clockwise  from  the  multiple-conductor  slot,  looking  down 
into  the  box.  The  lid  has  corresponding  projections  or  lugs 
which  enter  these  slots,  and  which,  in  position,  fit  snugly 
against  the  cable  ends.  The  cables  are  held  from  being 
pulled  out  by  Turk's-heads  worked  upon  them. 

To  prevent  the  cable  ends  from  accidentally  slipping  out 
of  the  slots  while  joints  are  being  made  between  them  before 
the  lid  is  put  on,  the  multiple  cable  is  secured  by  a  bolted 
collar  on  the  inside  of  the  box,  the  single-conductor  cables 
by  clipping  their  Turk's-heads  under  claw-like  radial  projec- 
tions cast  upon  the  inside  rim  between  the  slots. 

The  distribution  box,  7-conductor. — This  box  is  used  with 
multiple  cable,  7-conductor.  It  consists  of  two  circular  plates 
of  cast  iron  21  inches  in  diameter  and  three-fourths  of  an 
inch  thick  united  by  four  1-inch  bolts,  which  are  placed  in 
rounded  projections  forming  the  angles  of  a  square.  The 


SUBMARINE   MINING.  29 

cables  are  separately  clamped,  the  top  plate  overlapping  the 
clamp  straps.  The  multiple  cable  enters  on  one  side;  three 
single-conductor  cables  enter  on  the  opposite  side,  and  two 
on  each  of  the  intermediate  sides.  The  top  plate  is  provided 
with  a  lowering  ring. 

The  junction  boxes. — These  boxes,  in  different  sizes,  are 
used  in  splicing  multiple  and  single-conductor  cables;  they 
consist  of  two  rectangular  plates  of  iron  or  steel  united  by 
four  ^-inch  bolts  at  the  corners.  The  plates  are  hollowed 
in  the  middle  to  form  a  chamber  to  receive  the  Turk's-heads 
and  the  joints  connecting  the  conductors.  The  ends  of  the 
plates  are  curved  to  admit  the  cable  ends.  The  Turk's-heads 
are  clamped  to  the  lower  plate  by  straps  and  screw  bolts,  the 
cavity  of  the  upper  plate  covering  them  when  bolted  in  posi- 
tion. Each  cable  end  is  thus  made  fast  before  the  box  is 
closed. 

The  distribution-box  buoy. — This  buoy  is  used  to  mark  the 
position  of  the  distribution  box  during  the  planting  of  mines 
and  subsequently,  in  practice  and  in  service,  until  such  time 
as  the  mine  commander  desires  to  remove  it.  It  may  be 
either  a  can  or  a  keg  buoy — a  beer  keg  of  one-half  barrel 
capacity  is  well  suited  for  this  purpose. 

The  mine  buoy. — This  buoy  is  used  to  mark  the  position  of 
the  mine  when  planted.  It  may  be  a  small  can  buoy,  prefer- 
ably cork  filled,  or  a  piece  of  wood  with  a  hole  bored  through 
it.  The  size  of  the  buoy  is  determined  by  the  swiftness  of 
the  current.  It  is  attached  to  the  maneuvering  ring  of  the 
buoyant  mine  by  60  feet  of  J-inch  rope. 

The  measuring  reel  and  frame. — The  frame  consists  of  two 
longitudinal  pieces,  3  by  4  by  66  inches,  placed  17  inches 
apart,  center  to  center.  At  11 J  inches  from  each  end  two 
cross  pieces,  3  by  4  by  20  inches  in  length,  are  fastened  to  the 
longitudinal  pieces  with  through  bolts.  At  the  center  point 
of  these  cross  pieces  are  placed  standards,  3  by  4  by  16f 
inches,  which  have  journals  for  the  axle  of  the  reel,  counter- 
sunk in  their  upper  ends.  Two  iron  braces,  one  on  each  side, 
hold  each  standard  firmly  in  a  vertical  position.  An  iron 
clamp  is  also  attached  to  the  upper  ends  of  the  standards,  by 
nueans  of  which  the  axle  is  prevented  from  jumping  out  of 


30  SUBMARINE   MINING. 

the  journals.  Distance  from  center  to  center  of  standards  is 
43  inches. 

The  iron  axle  of  the  reel  is  1^-inch  round  iron,  54  inches  in 
length.  At  each  end  of  the  axle  a  screw  thread  is  cut  for  the 
nut  which  holds  the  crank  in  place.  Inside  the  screw  thread 
the  axle  is  squared  to  receive  the  socket  of  the  crank.  Two  col- 
lars prevent  the  wooden  reel  from  binding  on  either  stand- 
ard. The  cranks  are  of  the  usual  design.  The  drum  of  the 
reel  is  8^  inches  in  diameter;  heads  are  2J  inches  thick, 
made  in  two  layers,  cross-grained,  and  are  24  inches  in  diam- 
eter; length  of  drum  over  all  is  36  inches.  Iron  plates  are 
fastened  in  the  center  of  each  head,  through  which  the  axle 
passes.  The  reel  is  prevented  from  turning  on  the  axle  by 
keys. 

Three  f-inch  rods  pass  through  the  iron  plates  and  drum 
and  bind  these  parts  firmly  together. 

At  6  inches  from  the  ends  of  the  longitudinal  pieces  a  hole 
is  bored  to  receive  a  lag  screw,  -J  inch  by  6  inches,  by  means 
of  which  the  whole  apparatus  can  be  firmly  fastened  to  the 
deck. 

The  brake  is  a  piece  of  3  by  3  by  36  inch  hardwood,  used 
as  a  lever  to  bring  pressure  on  the  drumhead.  There  is  one 
for  each  side,  and,  when  not  in  use,  each  rests  on  one  of  the 
longitudinals,  being  held  in  place  at  one  end  by  two  staples 
and  at  the  other  end  by  a  bolt  and  pin. 

Near  the  drum  on  one  head  is  a  hole  through  which  the 
inner  end  of  the  measuring  line  can  be  passed  and  stapled  to 
the  outside  of  the  head. 

The  cable-reel  frame. — The  frame  is  made  in  two  parts 
which,  when  in  use,  are  held  in  proper  relative  positions  by 
means  of  two  iron  ties  provided  with  turnbuckles  at  their 
centers.  The  ends  of  these  ties  are  bent  over  at  right  angles 
and  fit  in  sockets  in  the  two  end  parts. 

Each  end  part  consists  of  a  standard  having  an  iron  head 
through  which  works  a  screw  turned  by  a  small  lever,  the  up- 
per end  carrying  a  journal  in  which  the  end  of  the  reel  axle 
rests.  The  lower  end  of  the  standard  rests  on  a  horizontal 
piece  and  has  a  diagonal  brace  on  each  side,  the  outer  ends 
of  these  braces  being  dovetailed  into  the  longitudinal  piece 


SUBMARINE    MINING.  31 

and  the  inner  ends  into  the  standard  near  the  top.  Dove- 
tailed into  the  longitudinal  piece  at  its  middle  point  is  a  piece 
extending  out  at  right  angles,  bottom  flush  with  bottom  of 
the  longitudinal.  A  diagonal  brace  similarly  fastened  pre- 
vents any  outward  movement  of  the  standard.  The  whole  is 
held  firmly  together  by  bolts  and  lag  screws. 

Lag  screws  are  also  provided,  by  means  of  which  the  ends 
of  the  frames  can  be  fastened  to  the  deck  of  the  vessel  if 
desired. 

The  reel  axle  is  2J  by  2|  inch  squared  iron,  rounded  at 
the  ends  for  6  inches  to  fit  the  journals  of  the  frame.  A 
disk  secured  by  a  set-screw  at  one  end  of  the  axle  and  the 
friction  brake  wheel  at  the  other  end  hold  the  axle  in  position 
with  respect  to  the  reel. 

The  brake  wheel  is  18  inches  in  diameter.  The  friction 
band  is  1^  inches  by  -J  inch,  and  is  fastened  at  one  end  to  one 
of  the  standards  of  the  frame.  The  other  end  is  attached  to  a 
lever  whose  fulcrum  is  also  attached  to  the  same  standard. 

Boat  telephones. — The  different  models  in  use  are  as  fol- 
lows: 

(a)  Model  1904. — The  system  consists  of  two  telephone 
hand  sets,  a  buzzer,  and  a  battery  of  dry  cells  of  about  8 
volts,  all  connected  in  series  by  means  of  cable  and  earth 
connections. 

In  operating  the  telephones  a  call  is  made  by  pressing  the 
button,  and  when  talking  the  lever  is  held  down. 

(b)  Model  1906. — The  system  consists  of  two  telephone 
hand  sets,  a  reactance  coil,  and  a  source  of  energy  that  will 
furnish  about  15  volts,  dry  cells  preferred,  connected  as 
shown  in  figure  11.     The  terminals  do  not  have  to  be  poled, 
as  the  receiver  is  not  in  the  primary  circuit  and  can  not  be 
demagnetized. 

To  regulate  the  buzzer,  remove  the  cap  in  the  base  nnd 
with  a  small  screw  driver  loosen  the  lock  nut  on  the  center 
screw  (a  small  portion  of  a  turn  is  all  that  is  necessary). 
With  a  smaller  screw  driver  the  screw  may  be  adjusted  to 
increase  or  decrease  the  rate  of  vibration,  increasing  or  de- 
creasing the  sound.  Then  tighten  the  lock  nut.  In  case  the 
contact  is  dirty  the  entire  buzzer  and  condenser  may  be 


32  SUBMARINE   MINING. 

removed  by  disconnecting  the  cord  and  removing  the  screw 
on  the  back  of  the  telephone  just  below  the  call  button.  As 
the  contacts  are  aluminum,  this  will  seldom  have  to  be  done. 

(c)  Model  1909. — The  system  consists  of  two  telephone 
hand  sets,  an  apparatus  box,  and  a  battery  of  from  7  to  10 
volts,  all  connected  as  shown  in  figure  12.  The  talking  and 
ringing  circuits  are  normally  open  at  the  talking  and  ring- 
ing buttons,  respectively. 

Apparatus  box. — Seven  dry  cells  in  series  should  be  con- 
nected to  the  posts  of  the  apparatus  box  marked  "  +  "  and 
"  — ,"  and  the  post  marked  "  G  "  connected  to  a  ground  plate. 

/Shore  hand  set. — The  blue  cord  of  the  shore  hand  set  should 
be  connected  to  the  ground  plate.  Either  of  the  red  cords 
of  the  shore  hand  set  should  be  connected  to  the  post  in  the 
apparatus  box  marked  "  L  "  and  the  other  to  the  conductor 
in  the  cable  that  is  to  be  used  for  telephoning  purposes. 

Boat  hand  set. — The  blue  cord  of  the  boat  hand  set  should 
be  connected  to  the  ground  plate  and  one  of  the  red  cords 
to  the  conductor  in  the  cable  to  which  the  hand  set  on  the 
shore  is  connected.  The  other  red  cord  is  free. 

Signaling. — From  figure  12  it  will  be  seen  that  in  either 
hand  set,  when  neither  the  ringing  nor  the  talking  switch  is 
closed,  a  condenser  within  the  hand  set  is  in  series  with  the 
transmitter  and  the  receiver,  so  that  the  practical  effect  is  to 
permit  an  alternating  or  variable  current  to  pass  through  the 
transmitter  and  the  receiver,  but  to  prevent  a  direct  or  con- 
tinuous current  from  so  doing. 

By  pressing  the  ringing  key  of  either  hand  set  the  circuit 
in  that  hand  set  is  closed  through  the  1,000  ohms  resistance 
and  the  receiver  to  ground.  Thus,  when  the  ringing  key  of 
the  boat  hand  set  is  pressed,  this  allows  the  direct  current 
from  the  battery  to  pass  (see  fig.  12)  through  f,  e,  d,  c,  "  B," 
b,  a,  line,  the  ringing  key,  1,000-ohm  resistance,  and  receiver 
of  the  boat  hand  set,  to  ground,  and  back  through  o  and  p 
to  battery.  Similarly,  a  circuit  through  the  battery,  f ,  "A," 
and  a,  is  made,  thus  placing  relays  "A"  and  "  B  "  in  parallel. 
The  relay  "  B  "  operates,  but  relay  "A,"  being  less  sensitive 
than  "  B."  does  not  operate.  Relay  "  B  "  closes  the  circuit  at 
1,  and  thus  completes  the  circuit  from  battery  through  f,  e,  d, 


ll 

*if 

3^ 

LAA. 

i 

b 

5, 

* 

SI    i|        ' 

SUBMARINE    MINING.  33 

c,  k,  1,  "  C,"  o,  p,  back  to  battery.  This  causes  relay  "  C  "  to 
operate  and  to  complete  a  local  circuit  from  battery  through 
f ,  e,  d,  k,  m,  s,  primary,  t,  vibrator,  p,  back  to  battery,  causing 
the  vibrator  to  vibrate  and  inducing  in  the  secondary  wind- 
ing of  the  induction  coil  an  alternating  current,  which  passes 
through  the  1  M.  F.  and  2  M.  F.  condensers,  through  the  hand 
sets  in  parallel,  and  by  alternately  increasing  and  decreasing 
the  attraction  of  the  receiver  magnets  for  their  diaphragms 
produces  a  loud  humming  sound  in  each  receiver. 

Similarly  the  shore  station  may  call  the  boat  station. 

Talking. — When  the  ringing  key  is  released  and  the  talk- 
ing key  is  depressed  the  1,000- ohm  resistance  is  cut  out  and 
the  condenser  in  the  hand  set  is  short  circuited.  The  current 
is  then  sufficient  to  operate  relay  "A,"  and  this  relay  in 
operating  allows  the  other  relays  to  resume  their  normal 
positions. 

When  the  variations  in  the  pressure  upon  the  transmitter 
diaphragm  in  either  hand  set  varies  the  resistance  of  the  cor- 
responding branch  circuit  a  slight  variation  in  the  current 
from  the  batltery  is  produced.  The  internal  resistance  of  the 
battery  is  sufficient  to  produce  a  slight  variation  in  its  ter- 
minal voltage.  The  resulting  variations  in  the  line  voltage, 
and  hence  in  the  drop  across  the  receivers,  produce  the  usual 
vibrations  in  the  receiver  diaphragms.  These  variations  also 
produce  slight  variations  in  the  current  through  the  primary 
winding  of  the  induction  coil,  resulting  in  greater  variations 
across  the  terminals  of  the  secondary  winding.  Since  the 
secondary  winding  is  in  series  with  the  battery,  the  practical 
effect  is  to  amplify  the  variations  in  the  line  voltage,  and 
hence  in  the  talking  currents. 

Successful  working  of  the  relays  is  obtained  only  by  a 
careful  adjustment  of  the  screws  which  regulate  the  throw 
of  the  armatures.  The  relay  "A"  is  located  in  front  of  the 
"  +  "  battery  post,  the  relay  "  C  "  in  front  of  the  "  G  "  post. 

In  addition  to  the  above  materiel  there  are  necessary 
for  the  mine  system  certain  electrical  instruments,  as  well 
as  tools,  appliances,  and  supplies  requiring  no  special  de- 
scription, which  are  enumerated  in  the  supply  list.  (Ap- 
pendix 8.) 

Figures  17a  and  17b,  at  the  end  of  the  book,  show  the  con- 
struction of  an  improvised  mine  target. 

11003°— 12 4 


CHAPTEE  III. 
LOADING  ROOM  DUTIES. 

Making  a  telegraph  joint. — The  insulation  is  removed  from 
the  ends  for  1-J  inches  and  the  wires  brightened.  The  ends 
to  be  joined  are  placed  across  each  other  about  one-third 
distance  from  the  insulation,  making  an  angle  of  about 
45°  with  each  other.  The  wires  are  grasped  firmly  at 
the  junction  and  each  free  end  wound  tightly  around  the 
other  wire  for  four  turns ;  the  winding  should  be  in  opposite 
directions.  The  ends  of  the  wires  are  trimmed  down  so  they 
will  be  smooth  and  present  no  sharp  points. 

When  wires  are  joined  with  brass  jointers  three-fourths 
inch  of  each  wire  is  bared  and  the  wires  are  inserted  in  the 
jointer;  each  end  is  crimped  with  pliers  in  the  direction  of 
the  longer  axis;  the  rest  of  the  jointer  is  crimped  and  the 
ends  or  sharp  points  rounded  off.  When  brass  jointers  are 
used  care  should  be  exercised  not  to  crimp  them  too  hard,  as 
the  wires  may  be  partly  cut  through  and  finally  broken. 
Special  care  must  be  used  with  the  fuse  leads,  as  the  second- 
ary circuit  of  the  mine  transformer  can  not  be  tested  after 
the  compound  plug  is  assembled. 

Insulating  a  joint. — A  piece  of  rubber  tape  about  2  inches 
long  is  used,  with  ends  cut  diagonally.  The  tape  is  stretched, 
and  starting  at  a  point  about  three- fourths  inch  back  on  the 
insulation,  with  the  long  edge  of  the  tape  on  the  inside,  it  is 
wound  around  the  joint  under  tension,  each  turn  covering 
the  previous  turn  about  one-third.  The  wrapping  is  con- 
tinued until  the  same  amount  of  insulation  is  covered  on  each 
side,  when  the  wrapping  is  worked  backward  over  the  joint 
and  the  end  is  secured  by  pressing  it  firmly  a  short  time  or 
placing  a  drop  of  cement  under  it. 
34 


SUBMARINE    MINING.  35 

Making  a  water-tight  joint. — The  two  ends  of  wire  are 
scraped  clean  for  about  three-fourths  of  an  inch  and  joined 
by  a  brass  jointer,  which  is  then  crimped.  The  insulation  is 
scraped  clean  about  2  inches  on  each  side  of  the  jointer  and 
covered  with  rubber  cement.  (Cement  is  not  absolutely 
essential.)  Two  strips  of  rubber  tape  are  cut  about  6  inches 
long,  with  diagonal  ends,  and  stretched.  Beginning  about 
1J  inches  along  the  insulation,  the  tape,  with  the  long  edge 
on  the  inside,  is  wrapped  firmly  and  tightly  until  about  one- 
fourth  of  an  inch  of  the  insulation  on  the  other  side  is  cov- 
ered ;  it  is  wound  back  and  forth  over  the  joint  so  as  to  taper 
toward  the  ends.  The  other  piece  of  tape  is  used,  beginning 
at  the  other  end  and  wrapping  as  before.  The  finished  insu- 
lation should  be  thick  at  the  middle  and  taper  toward  the 
ends.  It  should  be  firm  and  tight.  The  insulation  is  cov- 
ered with  tin  foil,  wrapped  with  protective  tape,  and  vulcan- 
ized for  about  30  seconds.  The  protective  tape  and  tin  foil 
are  then  removed,  the  joint  inspected,  and  new  protective 
tape  wrapped  on,  using  two  pieces,  starting  at  opposite  ends 
and  finally  ending  each  beyond  the  center. 

Making  a  Turk's-head. — The  cable  is  trimmed  square  and  a 
wrapping  of  four  or  five  turns  of  marline  is  made  about  15 
inches  from  the  end.  The  collar,  flat  side  first,  is  slipped 
on  until  it  rests  on  the  marline ;  the  iron  wires  are  bent  back 
regularly  over  the  collar.  The  jute  wrapping  is  unwound 
to  the  collar  and  trimmed,  and  all  the  iron  wires  are  cut  with 
the  pliers,  removing  all  but  4  inches  and  6  inches  from 
alternate  strands;  the  iron  wires  are  bent  separately  to  fit 
the  collar  closely  (making  two  right  angles  with  the  pliers), 
and  the  ends  arranged  smoothly  along  the  cable;  the  end  of 
a  piece  of  marline  is  engaged  under  one  of  the  wires  near 
the  collar  and  wrapped  regularly  and  closely  around  the 
cable,  and  the  free  end  of  marline  secured  with  two  half 
hitches.  About  15  feet  of  marline  are  required  for  single 
conductor  cable ;  24  feet  for  multiple  cable. 

Testing  fuses. — The  following  apparatus  is  used  for  testing 
in  the  loading  room:  A  double-pole  double-throw  switch,  a 


36  SUBMARINE    MINING. 

150- volt  voltmeter,  and  sufficient  dry  cells  to  give  a  full  throw 
when  using  the  lower  scale  of  the  voltmeter.  The  apparatus 
is  connected  up  on  the  testing  table  so  as  to  make  resistance 
measurements  by  the  voltmeter  method.  To  test  fuses,  leads 
are  carried  from  the  switch  to  an  iron  or  other  suitable  recep- 
tacle outside  of  the  building  and  the  fuse  leads  joined 
thereto.  A  full  deflection  should  be  obtained  when  the  cir- 
cuit is  closed  through  the  fuses. 

Preparing  a  compound  plug  for  service. — The  transformer  to 
be  used  is  first  tested  for  a  good  circuit  between  the  red  wires, 
a  poor  circuit  between  the  ends  of  the  black  wire,  a  good  cir- 
cuit between  the  black  or  primary  lead  and  the  reactance 
terminal,  no  circuit  between  the  red  and  black  wires,  and  no 
circuit  between  any  wire  and  the  case.  The  resistance  of  the 
circuits  is  determined  by  the  voltmeter  method.  The  upper 
end  of  the  black  wire  (see  fig.  8)  is  prepared  for  use  by 
baring  the  wire  for  about  one-half  inch  and  securing  it  to 
the  binding  post  in  the  neck  of  the  transformer.  The  ball 
seat  is  screwed  home.  The  spring  plate,  distance  ring,  and 
ball  are  placed  in  the  circuit-closer  cap,  which  is  held  in- 
verted and  the  transformer  screwed  into  it,  the  threads  being 
coated  with  ruberine. 

(a)  Old  model,  brass  fuse  can. — Starting  with  the  compound 
plug  dismantled. 

A  piece  of  loading  wire  is  cut  about  3  feet  long  and  the 
ends  bared.  One  end  is  joined  by  a  telegraph  joint  to  the 
primary  terminal  of  the  transformer  and  the  joint  is  taped. 
This  wire  and  the  two  secondary  wires  are  drawn  through 
the  fuse  can,  which  is  screwed  on  the  transformer,  the  threads 
of  the  latter  having  first  been  coated  with  ruberine. 

Two  mine  service  fuses,  which  have  been  tested  for  con- 
tinuity of  circuit,  are  connected  in  multiple  across  the  sec- 
ondary (red)  terminals  and  the  joints  taped. 

The  can  is  held  vertically  and  the  explosive,  if  trotol, 
poured  in  up  to  the  screw  threads  for  the  fuse-can  cap;  if 
dynamite,  inclosed  in  a  cloth  bag  and  placed  in  the  can. 
The  fuses  are  embedded  in  the  explosive. 


SUBMAKINE   MINING.  37 

The  loading  wire  is  drawn  through  a  lead  washer  and  the 
fuse-can  cap ;  the  latter,  its  threads  having  been  coated  with 
ruberine,  is  screwed  into  place. 

A  rubber  packing  is  pushed  over  the  loading  wire  into  the 
stuffing  box  in  the  fuse-can  cap,  a  brass  gland  is  threaded 
down  so  that  it  is  close  against  the  rubber  packing,  and  the 
follower  in  screwed  home  with  moderate  pressure.  The 
lower  tube  is  screwed  into  place,  compressing  a  lead  washer 
between  it  and  the  fuse-can  cap.  The  threads  of  the  follower 
and  lower  tube  are  coated  with  ruberine. 

The  loading  wire  is  drawn  through  a  lead  washer  and  the 
hole  in  the  plug  proper,  and  the  latter  screwed  hard  against 
the  lower  tube. 

A  rubber  packing  and  a  brass  gland  are  placed  upon  the 
loading  wire  and  forced  into  their  seat  in  the  plug  proper  by 
means  of  the  follower,  the  threads  of  which  have  been  coated 
with  ruberine. 

(b)  Rubber  fuse  can. — Starting  with  the  compound  plug 
dismantled. 

Two  mine  service  fuses,  which  have  been  tested  for  con- 
tinuity of  circuit,  are  cut  with  9-inch  leads,  wires  bared  for 
about  1  inch  and  connected  in  multiple.  A  piece  of  loading 
wire  is  cut  about  3  feet  long  and  the  ends  bared  for  telegraph 
joints.  It  is  threaded  through  a  hole  in  a  cake  of  dry  gun- 
cotton.  The  twTo  fuses  are  inserted  by  pushing  each  sepa- 
rately into  the  same  hole  and  the  loading  wire  drawn  up 
until  it  is  the  same  length  above  the  cake  as  the  fuse  leads. 

Three  other  primer  cakes  are  threaded  on  the  wire;  two 
above  the  fuses,  and  one  below.  This  arrangement  will  leave 
the  fuses  in  the  third  cake.  The  cakes  are  held  in  one  hand 
with  the  fuse  leads  upright,  and  the  fuse  can  slipped  over  the 
cakes,  being  careful  to  thread  the  fuse  leads  and  loading 
wire  through  the  opening. 

The  screw  threads  of  the  fuse-can  cap  are  covered  with 
ruberine  and  it  is  screwed  firmly  into  place  onto  the  fuse  can. 
The  stuffing  box  of  the  cap  is  assembled. 

The  plug  proper  is  held  upright  in  a  vise.  The  fuse  can, 
the  threads  of  the  cap  having  been  coated  with  ruberine,  is 


38  SUBMARINE    MINING. 

screwed  home  and  secured  by  its  set  screw.  The  loading 
wire  must  be  pulled  through  the  opening  in  the  plug  proper 
with  extreme  care.  It  must  not  be  injured  in  placing  the 
fuse  can  in  position  and  in  screwing  it  home.  The  trans- 
former leads  are  cut  about  6  inches  long,  and  the  ends  bared 
for  1  inch.  The  brass  collar  is  screwed  on  the  transformer ; 
a  little  ruberine  on  the  screw  threads  facilitates  the  opera- 
tion. The  connecting  collar  is  slipped  over  the  fuse  leads 
and  loading  wire  and  allowed  to  rest  on  the  fuse  can.  The 
transformer  is  supported  by  allowing  two  of  the  connect- 
ing bolts  to  slip  into  the  holes  in  the  collar;  telegraph  joints 
or  brass  jointers  may  be  used  between  the  secondary  leads 
and  the  fuses  and  between  the  primary  lead  and  the  loading 
wire.  The  joints  are  wound  with  rubber  tape,  care  being 
taken  that  there  are  no  sharp  ends  to  cut  through  the  tape. 

The  transformer  is  raised  vertically  above  the  fuse  can 
until  the  lead  wires  are  extended.  It  is  lowered  and  at  the 
same  time  the  leads  are  coiled  in  the  base  of  the  transformer. 
As  the  transformer  and  collar  approach  their  position  on 
the  connecting  bolts,  the  connecting  collar  is  screwed  on  the 
transformer,  the  threads  of  the  transformer  having  been 
covered  wih  ruberine.  The  connecting  collar  will  take  care 
of  the  remainder  of  the  leads  and  joints.  The  set  screw  in 
the  connecting  collar  is  screwed  home;  the  brass  collar  is 
placed  on  the  connecting  bolts  and  secured  in  position  by  the 
nuts  and  cotter  pins. 

The  lips  of  the  fuse  can  and  connecting  collar  are  covered 
with  a  thin  covering  of  rubber  cement.  A  piece  of  rubber 
tape  is  cut  about  18  inches  long  and  laid  around  this  opening 
without  stretching.  A  piece  of  protective  tape  is  cut  about 
18  inches  long  and  laid  over  the  rubber  tape  with  consider- 
able stress.  This  forces  the  soft  tape  over  the  lips  on  the  con- 
necting collar  and  the  fuse  can  and  makes  a  tight  but  flexible 
joint.  The  stuffing  box  in  the  plug  proper  is  prepared  as 
under  (a). 

Great  care  must  be  taken  not  to  injure  the  insulation  of 
the  loading  wire  in  tightening  up  the  follower  in  the  stuffing 
box  of  the  fuse  can  or  of  the  plug  proper. 


SUBMAKINE   MINING.  39 

(c)  Trotol  fuse  <can. — Starting  with  the  compound  plug 
dismantled. 

Two  mine  service  fuses,  which  have  been  tested  for  con- 
tinuity of  circuit,  are  cut  with  12-inch  leads,  the  wires  bared 
for  1  inch  and  connected  in  multiple.  A  piece  of  loading 
wire  is  cut  about  3  feet  long  and  the  ends  bared  for  telegraph 
joints.  The  loading  wire  is  threaded  through  the  fuse  can 
and  cap.  The  threads  of  the  fuse  can  are  covered  with 
ruberine.  The  can  is  screwed  into  the  cap.  The  threads  of 
the  connecting  collar  are  coated  with  ruberine  and  the  collar 
is  screwed  down  entirely.  The  loading  wire  should  project 
about  4  inches  above  the  connecting  collar.  The  stuffing  box 
of  the  cap  is  prepared.  The  plug  proper  is  held  upright  in 
a  vise.  The  fuse-can  cap,  its  threads  having  been  coated 
with  ruberine,  is  screwed  firmly  into  the  plug  proper  by 
means  of  a  spanner  wrench.  The  loading  wire  must  be 
pulled  through  the  opening  in  the  plug  proper  with  extreme 
care.  It  must  not  be  injured  in  placing  the  fuse  can  in 
position  and  screwing  it  home. 

The  fuses  are  inserted  in  the  fuse  can,  which  is  filled  with 
trotol  to  the  top  of  the  connecting  collar.  The  transformer 
leads  are  cut  4  inches  long  and  the  ends  bared  for  1  inch. 
The  threads  of  the  brass  collar  are  covered  with  ruberine. 
It  is  screwed  on  the  transformer.  The  latter  is  raised  verti- 
cally above  the  fuse  can  and  lowered  on  the  connecting  bolts. 

Telegraph  joints  are  made  between  the  secondary  leads 
and  the  fuses  and  the  primary  lead  and  the  loading  wire. 
The  joints  are  wound  with  rubber  tape,  care  being  taken  that 
no  sharp  ends  cut  through  the  tape.  The  leads  and  joints 
are  coiled  in  the  base  of  the  transformer.  The  connecting 
collar,  its  threads  having  been  covered  with  ruberine,  is 
screwed  upon  the  transformer  against  the  brass  collar.  The 
bolt-securing  nuts  and  cotter  pins  are  placed  in  position. 
The  stuffing  box  in  the  plug  proper  is  assembled  as  under  (a). 

The  actual  resistance  of  the  assembled  plug  in  the  vertical 
and  the  horizontal  positions  is  determined  by  testing  with 
a  voltmeter. 


40  SUBMARINE   MINING. 

In  service,  after  the  loaded  plug  tests  out  satisfactorily,  all 
set  screws  are  set  up. 

When  compound  plugs  are  prepared  for  drill  or  for  in- 
struction purposes  the  use  of  ruberine  or  other  waterproofing 
material  on  the  screw  threads  is  omitted ;  care  must  be  taken 
that  the  transformer  leads  are  not  needlessly  shortened. 

Loading1  a  mine. — The  mine  case  is  carried  from  the  store- 
room to  the  loading  room  and  placed  on  a  loading  skid  or 
other  receptacle  with  the  loading  hole  up.  The  plug  is  re- 
moved and  the  screw  threads  are  thoroughly  cleaned.  The 
explosive  detail  brings  in  a  box  of  explosive  from  the  explo- 
sive house  and  inserts  a  loading  funnel  into  the  loading  hole. 
The  charge  for  a  32-inch  mine  case  is  100  pounds  of  explo- 
sive. For  the  larger  cases,  the  charge  should  be  the  maxi- 
mum that  the  conditions  warrant ;  it  is  specified  at  present  as 
200  pounds,  though  larger  charges  are  desirable  if  enough 
explosive  can  be  obtained  and  the  excess  buoyancy  of  the  case 
will  warrant  the  use  of  more  than  200  pounds.  The  car- 
tridges of  dynamite,  the  trotol,  or  the  blocks  of  guncotton  are 
inserted  by  hand  and  so  placed  in  the  mine  case  that  there 
will  be  ample  room  for  inserting  the  compound  plug.  Only 
one  box  of  explosive  for  each  mine  being  loaded  is  brought 
into  the  loading  room  at  one  time.  After  the  proper  amount 
of  explosive  has  been  placed  in  the  mine  case  the  screw 
threads  are  thoroughly  cleaned  with  button  brushes  and  then 
coated  with  ruberine  or  other  material  to  prevent  access  of 
water.  The  compound  plug,  with  its  screw  threads  similarly 
coated,  is  screwed  home  with  the  socket  wrench,  a  lead  washer 
being  used  between  the  plug  and  mine  case.  A  bar  put 
through  holes  in  the  sides  of  the  skids  and  through  the 
maneuvering  ring  will  prevent  the  case  from  falling  over  and 
from  turning  while  the  compound  plug  is  being  screwed 
home. 

In  order  to  insure  setting  the  compound  plug  tight,  it  is 
advisable  to  tap  the  end  of  the  lever  of  the  socket  wrench  a 
few  times  with  a  large  mallet  or  a  large  wooden  bar.  The 
mine  cap  is  bolted  on  and  the  mine  put  in  a  tank  for  test. 
If  time  admits,  it  may  remain  in  the  water  24  hours.  It 


SUBMAKINE   MINING.  41 

should  show  practically  the  same  resistance  as  the  compound 
plug.  If  this  test  be  made,  the  loading  wire  must  be  long 
enough  for  this  purpose. 

Upon  completion  of  this  test  the  mine  is  taken  from  the 
tank,  the  loading  wire  pushed  inside  the  cap  to  avoid  injury 
in  handling,  and  the  loaded  mine  taken  to  the  planting  wharf. 

The  precautions  to  be  observed  in  handling  explosives  and 
loading  mines  are  given  in  Appendix  1. 


CHAPTEK  IV. 

LOCATING  DISTRIBUTION  BOX,  LAYING  MULTIPLE 
CABLE,  AND  MARKING  OUT  MINE  FIELD. 

(NoTfc. — The  operations  in  Chapters  IV  and  V  are  described  in 
what  is  thought  to  be  the  logical  order,  but  circumstances  may  alter 
their  sequence,  and,  in  fact,  several  of  the  steps  may  be  carried  on 
simultaneously. ) 

For  the  work  on  the  water  there  will  be  needed  five  boats, 
viz,  a  mine  planter  or  suitably  fitted-up  heavy  tug,  a  small 
tug  or  heavy  launch  called  the  distribution-box  boat5  and 
three  launches  or  yawls.  The  capacity  of  the  planter  is  such 
that  a  group  of  19  mines  can  be  handled  at  one  time. 

The  instructions  to  be  observed  by  the  master  of  a  mine 
planter  in  marking  out  a  mine  field  and  in  planting  mines 
are  to  be  found  in  Appendix  No.  6. 

Determining  location  for  distribution  box. — From  an  exami- 
nation of  the  chart,  or  of  the  approved  scheme  for  mining, 
the  locations  of  the  lines  and  groups  of  mines  are  deter- 
mined. A  distribution  box  is  to  be  placed  about  350  feet  in 
rear  of  the  center  of  each  group  of  mines.  The  locations  for 
the  distribution  boxes  are  marked  on  the  plotting  board  and 
their  azimuths  from  each  of  the  ends  of  the  horizontal  base 
or  their  azimuth  and  range  from  the  vertical  base  station  are 
determined. 

Marking  location  of  distribution  box. — An  anchor  with  buoy 
attached  is  placed  upon  the  deck  of  a  small  tug  and  carried 
out  to  one  of  the  selected  spots.  By  a  system  of  signals  the 
boat  is  directed  to  the  location  determined  and  there  the 
anchor  is  thrown  overboard.  The  locations  for  the  other 
distribution  boxes  are  marked  in  a  like  manner. 

Laying  multiple  cable. — The  cable  reel  is  placed  upon  the 
forward  deck  of  the  planter  and  raised  on  the  jacks.  The 

42 


SUBMARINE   MINING.  43 

planter  then  proceeds  as  near  the  mining  casemate  as  the 
depth  of  water  permits,  and  one  end  of  the  cable  is  passed 
ashore,  either  by  a  launch,  by  yawls,  or  by  any  other  suitable 
method.  In  case  the  planter  can  not  approach  nearer  the 
shore  than  100  yards  it  will  be  necessary  to  coil  more  than 
enough  cable  to  reach  the  shore  in  a  figure  of  eight  in  a 
yawl,  which  is  then  towed  toward  the  desired  point  on  shore, 
the  men  aboard  the  yawl  paying  out  the  cable  as  it  proceeds. 
This  end  is  drawn  in  through  the  conduit  or  gallery  to  the 
casemate  or  terminal  hut.  It  may  be  secured  by  taking  a 
telegraph  hitch  around  it  with  a  chain  and  spiking  the  chain 
to  some  heavy  timbers  or  fastening  it  to  some  holdfast. 
When  cable  ends  have  already  been  laid  they  will  be  picked 
up  and  joined  to  the  multiple  cable  for  the  groups. 

The  shore  end  having  been  secured,  the  planter  moves  out 
to  the  position  of  the  distribution  box,  unreeling  the  cable 
as  it  goes.  If  the  water  be  very  deep,  a  friction  brake  must 
be  extemporized  to  prevent  the  reel  from  overrunning. 
(While  the  planter  is  laying  the  cable,  the  casemate  party 
tags  and  attaches  the  shore  end  as  explained  later.)  To  pre- 
vent kinks  as  far  as  possible  cable  should  be  laid  with  as 
much  tension  as  practicable. 

If  the  cable  is  not  long  enough,  a  second  one  must  be 
joined  to  it.  This  is  preferably  done  by  passing  the  ends  to 
a  small  boat.  The  junction  is  made,  either  using  a  junction 
box  with  Turk's-heads  and  taped  joints,  or  opening  back  the 
armor  for  about  5  feet  from  the  ends,  making  taped  joints, 
protecting  them  with  tape,  and  then  rewrapping  the  armor 
and  seizing  the  ends  with  wire.  Care  must  be  taken  to  join 
the  proper  conductors  of  the  two  ends. 

In  the  meantime  the  distribution-box  boat  with  a  detach- 
ment of  one  noncommissioned  officer  and  five  men  takes  the 
distribution  box  and  moves  out  to  the  spot  marked  by  the 
buoy.  It  picks  up  the  buoy  and  makes  fast  to  the  anchor 
line. 

The  planter  continues  laying  the  multiple  cable  until  it 
reaches  the  distribution-box  boat.  The  multiple  cable  is  then 
cut  and  the  end  passed  to  the  distribution-box  boat,  usually 
by  a  heaving  line.  The  cable  is  lashed  to  the  boat ;  a  Turk's- 


44  SUBMARINE   MINING. 

head  is  worked  upon  the  end  and  then  secured  in  the  distri- 
bution box.  As  a  precautionary  measure  for  the  recovery  of 
the  distribution  box,  should  it  be  lost  overboard  during  mine 
planting,  it  is  well  to  have  the  multiple  cable  buoyed  about 
100  yards  in  rear  of  the  distribution  box. 

In  case  it  may  be  desired  not  to  use  the  distribution  box  at 
once,  the  separate  conductors  of  the  multiple  cable  should  be 
tagged,  tested,  and  insulated.  The  cable  should  be  buoyed 
and  dropped  overboard  to  be  recovered  subsequently. 

Identifying-,  tagging,  and  testing  the  conductors  of  the  mul- 
tiple cable. — Tagging. — In  the  casemate  the  conductors  are 
separated,  carefully  identified,  tagged,  and  attached  to  the 
corresponding  terminal  of  the  terminal  bar  on  the  operating 
board.  The  mine  switch  for  No.  19  is  opened  and  the  tele- 
phone terminal  attached  to  its  stud  so  as  to  use  No.  19  for 
communicating  with  the  distribution-box  boat.  The  ends  in 
the  distribution-box  boat  are  separated,  one  terminal  of  a  boat 
telephone  is  attached  to  No.  19,  and  the  other  earthed  either 
by  attaching  to  the  cable  armor  or  to  an  earth  plate  hanging 
overboard  in  the  water.  Communication  is  thus  established 
with  the  operator  in  the  casemate.  Nos.  1,  13,  and  19  are 
picked  out  easily;  the  remaining  ones  are  tagged  in  contra- 
clockwise  direction. 

Verifying  the  tagging. — The  casemate  is  then  notified  that 
the  boat  party  is  ready  to  check  the  tagging.  This  is  done  as 
follows :  The  power  switches  on  the  operating  board  are  all 
closed,  except  19,  and  direct  current  put  on  the  cable  by  closing 
switch  No.  3  up.  The  casemate  operator  then  directs  the  boat 
party  to  earth  in  regular  succession  the  various  conductors. 
This  is  done  most  quickly  by  touching  the  conductor  to  the 
cable  armor.  The  corresponding  automatic  switch  on  the 
operating  board  should  drop.  Any  errors  in  tagging  de- 
tected by  this  test  should  be  corrected  at  once.  This  test  also 
checks  the  continuity  of  circuit  of  each  conductor. 

Insulation  test. — The  operator  then  directs  the  boat  party 
to  prepare  the  cable  end  for  insulation  test.  This  is  done  by 
separating  the  conductors,  holding  them  in  the  air,  and 
drying  them  if  necessary. 


SUBMARINE   MINING.  45 

When  prepared,  word  is  sent  to  the  casemate  operator,  who 
tests  as  follows :  He  closes  switch  No.  7  up.  This  throws  D. 
C.  power  on  the  mil-ammeter  plug  of  the  operating  board 
and  introduces  in  the  circuit  the  mil- ammeter  and  its  protec- 
tive lamp.  The  green  lamp  is  then  unscrewed  and  the  mil- 
ammeter  plug  used  on  the  D.  C.  jaw. 

If  there  be  no  leak  in  the  multiple  cable,  since  the  ends  at 
the  distribution-box  boat  are  held  in  the  air,  there  will  be  no 
appreciable  reading  of  the  mil-ammeter. 

If  there  be  a  leak,  this  fact  will  be  revealed  by  a  reading 
on  the  mil-ammeter.  To  discover  the  particular  conductor 
or  conductors  on  which  this  leak  exists,  each  power  switch  is 
opened  in  succession  and  the  mil-ammeter  plug  inserted  on 
the  jaw  of  the  power  switch. 

No.  19  is  now  tested  in  the  same  way  by  first  shifting  both 
telephones  to  No.  1,  the  boat  end  being  held  in  the  air.  The 
operator  reports  the  result  of  the  test. 

Upon  completion  of  these  tests  the  power  is  turned  off. 
Post  power  should  not  be  used  for  testing,  because  the  nega- 
tive side  of  the  post  power  may  be  grounded. 

Marking1  out  the  mine  field. — In  using  automatic  anchors  it 
is  not  necessary  to  mark  the  mine  field ;  but  in  using  mush- 
room anchors  it  is  generally  done.  The  material  required 
consists  of  1  measuring  line  with  reel  and  frame,  5  anchors, 
5  keg  buoys,  and  5  raising  ropes. 

A  buoyed  anchor  is  dropped  about  350  feet  in  front  of 
the  distribution-box  buoy.  This  marks  the  position  of  mine 
No.  10  and  of  the  center  of  the  group.  * 

This  marking  buoy  is  picked  up  by  a  launch  which  makes 
fast  to  the  anchor  rope.  The  planter  now  passes  to  the 
launch  one  end  of  a  measuring  line,  which  has  marks  at 
280,  300,  350,  580,  and  600  feet.  These  marks  may  be  made 
by  painting  3  feet  of  the  measuring  line  some  distinctive 
color  at  the  designated  points.  The  planter  moves  out 
slowly  along  the  line  to  be  occupied  by  the  mines,  unreeling 
the  measuring  line  as  it  goes,  and  drops  buoys  at  the  300  and 
600  foot  marks.  It  then  returns  and  does  the  same  for  the 
other  side  of  the  line.  These  five  buoys  mark  the  line  to  be 


46  SUBMARINE   MINING. 

occupied  by  the  mines,  indicate  the  positions  of  mines  Nos. 
4,  7,  10,  13,  and  16,  and  in  addition  cut  up  the  distance  into 
300-foot  lengths,  which  enable  the  planter  to  plant  mines  at 
a  close  approximation  to  100  feet  apart. 

Taking  soundings  on  line  of  mines. — When  automatic  an- 
chors are  used,  such  information  as  may  be  required  about 
depth  of  water  may  usually  be  obtained  from  charts.  This 
may  not  be  sufficiently  accurate  for  planting  with  ordinary 
anchors.  In  the  latter  case  .soundings  must  be  taken  at  the 
spots  where  the  mines  are  to  be  planted. 

These  soundings  are  made  from  the  launches.  The 
launches  take  a  measuring  line  marked  at  every  100  feet, 
stretch  it  between  the  planted  buoys,  and  take  the  soundings 
at  every  100- foot  point.  The  soundings  are  recorded  in  a 
blank  book  showing  the  number  of  the  corresponding  mine 
and  state  of  the  tide.  It  may  be  found  more  satisfactory  to 
hold  one  end  of  the  measuring  line  at  the  buoy  and  circle 
across  the  line  of  mines  with  the  launch,  getting  the  sound- 
ing at  the  point  of  crossing. 

Preparing  mooring  ropes. — The  mooring  ropes  are  cut  off 
with  square  ends,  and  the  ends  passed  through  the  holes  in 
the  mooring  sockets.  The  strands  and  wires  are  untwisted 
and  spread  out  for  a  length  equal  to  the  length  of  the  socket 
hole.  The  rope  is  pulled  back  until  the  ends  are  about  flush 
with  the  top  ends  of  the  hole ;  a  piece  of  marline  is  tied  about 
the  rope  below  the  socket.  If  necessary  to  hold  the  socket, 
a  piece  of  burlap  may  be  wrapped  around  below  the  socket, 
and  a  fold  allowed  *to  fall  over  the  hand.  Generally,  means 
can  be  found  to  set  the  socket  upright  while  pouring  full  of 
alloy.  The  alloy  consists  of  9  parts  of  lead  and  1  part  of 
antimony  melted  together.  A  melting  pot  heated  by  a 
plumber's  furnace,  or  preferably  a  Khotal  lamp,  is  used  for 
this  purpose.  Great  care  must  be  taken  to  see  that  there  is 
no  oil  or  water  on  the  socket  or  mooring  rope  before  pouring 
(the  alloy. 

The  length  of  the  mooring  rope  for  buoyant  mines  No.  32 
equals  the  depth  at  low  tide,  less  15  feet.  This  allows  5  feet 


SUBMARINE   MINING.  47 

for  the  length  of  the  mine,  anchor,  and  shackles,  and  10  feet 
for  submergence.  When  thimbles  and  clips  are  used  the 
mooring  rope  is  cut  3  feet  longer  and  is  bent  back  a  foot  and 
a  half  at  each  end  for  the  thimbles  and  clips. 

For  the  larger  mine  cases,  an  additional  allowance  must 
be  made  for  the  length  of  the  cylindrical  part  of  the  case. 

Each  mooring  rope  is  carefully  tagged  at  each  end  with 
the  number  of  the  corresponding  mine. 


CHAPTER  V. 


ASSEMBLING  AND  PLANTING  MINES. 

NOTE. — The  instructions  to  be  observed  by  the  master  of  a  mine 
planter  in  marking  out  a  mine  field  and  in  planting  mines  are  to  be 
found  in  Appendix  No.  6. 

The  planter  detail. — This  consists  of  the  chief  planter  and 
3  noncommissioned  officers  and  16  privates,  distributed  in 
three  details,  as  follows:  One  noncommissioned  officer  and 
six  privates  on  each  side  of  the  planter  and  one  noncommis- 
sioned officer  and  four  privates  aft. 

Tools  and  supplies. — The  tools  and  supplies  to  be  taken 
aboard  for  the  work  described  are : 


On  the  planter. 

On  distribution-box  boat. 

In  each  yawl. 

Alcohol. 

Alcohol. 

Anchor,  boat. 

Anchors. 

Anchors,  boat  (2). 

Anchor  line. 

Axe. 

Axe. 

Boat  hook. 

Boat  hooks. 

Boat  hook. 

Heaving  line. 

Buoy,  key. 
Buoys,  mine. 
Cable  cutter. 

Boat  telephone  with  connec- 
tors and  earth  plate. 
Breaker  of  drinking  water. 

Life  buoy. 
Life  preservers,  1   for  each 
man. 

Cables,  multiple. 

Buoy. 

Marline. 

Cables,  single  conductor. 
Cable  tags. 
Clips,  cable. 

Cable  tags. 
Compass,  boat. 
Distribution  box. 

Megaphone. 
Oars  and  locks  (7). 
Sounding  line. 

Cotter  pins. 
Crank   handle   for   automatic 

Flags,  boat  (2). 
Gasoline  (tankful). 

anchor. 

Green  light. 

Dry  cells. 

Hammers. 

Grappling  hooks. 

Heaving  lines. 

Hammers. 

Kerosene. 

Heaving  lines. 

Knives,  submarine-mine. 

Kerosene. 

Lamps,  alcohol  (2). 

Knives,  submarine-mine. 

Lashings. 

Lamps,  alcohol  (2). 

Life  buoys  (2). 

Life  buoys  (3). 

Life  preservers,  one  for  each 

Marline. 

man. 

Marlinespikes. 

Marline. 

Matches. 

Marlinespike. 

Megaphone. 

Matches. 

Mines. 

Megaphone. 

Monkey  wrenches. 
Nuts. 

Monkey  wrenches. 
Notebook  and  pencil. 

Ropes,  mooring. 

Red  light. 

Rcxpcs  r&ising. 

Rope,  raising. 

Shackles,  anchor. 
Shackles,  mine. 

Ropes,  buoy  (2). 
Shackles. 

Shoes,  mine-cap. 

Tools  and  materials  to  make 

Sister  hooks. 
Spring  balance. 

Turk's-heads  and  joints. 
Waste. 

Stamping  outfit. 

White  lights  (2). 

Tools  and  materials  necessary 

to  make   Turk's-heads   and 

joints. 

Voltmeter. 

Washers. 

** 

Waste. 

Wire,  soft-drawn  copper. 

Wrench,  socket,  for  automatic 

anchor. 

SUBMARINE   MINING. 


49 


Preparing  mine  cables. — A  reel  of  single-conductor  cable 
is  taken  from  the  tank  and  placed  on  a  cable-reel  frame.  A 
piece  20  feet  long  is  cut  off  the  end  to  eliminate  the  part 
which  was  above  water  during  storage.  The  cable  for  the 
mines  is  now  unreeled,  cut  to  the  following  lengths  plus  twice 
the  approximate  depth  of  the  water,  and  each  end  carefully 
tagged  with  the  number  of  the  corresponding  mine.  A 
Turk's-head  is  made  on  each  end. 


No.  11 

No.  12 

No.  13 

No.  14 

No.  15 

No.  16 

No.  17_ 1,025 

No.  18 1,  225 

No.  19 1,425 


Feet. 
425 
475 
525 
625 
725 
825 


Feet. 

No.  1 1,425 

No.  2 1,225 

No.  3 1,025 

No.  4 825 

No.  5 725 

No.  6 625 

No.  7 525 

No.  8 475 

No.  9 425 

No.  10 375 

The  mine  cables  are  coiled  in  figure  8's.  In  order  to  secure 
uniformity  in  the  size  of  the  coils,  they  may  be  coiled  on  a 
rack  (improvised  at  the  post).  This  rack  is  made  of  one 
12-foot  length  of  4  by  6-inch  scantling,  crossed  at  right  angles 
by  two  6-foot  lengths  (4  by  6  inch)  placed  5  feet  apart. 
Four  1-inch  holes  are  bored  through  each  of  the  timbers 
about  2  feet  from  each  of  the  crossings,  and  a  2- foot  length 
of  gas  pipe  is  inserted  in  each  hole.  These  pipes  make  the 
form  on  which  the  coils  are  made. 

A  cable  must  be  coiled  for  planting  so  that  both  ends  are 
free,  one  to  be  passed  to  the  distribution-box  boat,  the  other  to 
be  carried  forward  on  the  planter  and  attached  to  the  mine. 
This  is  accomplished  by  starting  the  coil  about  135  feet  from 
the  mine-cap  end,  the  approximate  length  required  to  run  for- 
ward when  using  a  mine  planter.  The  cable  is  coiled  on  the 
form,  spreading  out  the  laps  at  the  center  to  reduce  the 
height  at  that  point,  until  the  entire  length  is  coiled.  The 
outer  loops  and  the  center  of  the  figure  8  coil  are  lashed, 
leaving  the  ends  sufficiently  long  to  lash  the  part  of  the  cable 

11003°— 12 5 


50  SUBMARINE   MINING. 

remaining  uncoiled.  The  mine-cap  end  of  the  cable  is  then 
coiled  on  top  of  the  coil  and  lashed  with  the  ends  of  the  rope. 
•  Single-conductor  cables  when  coiled  should  be  tested  for 
continuity  of  circuit  and  grounds  before  being  placed  aboard 
the  planter. 

For  continuity  of  circuit  the  two  ends  of  the  cable  are  con- 
nected to  a  battery  and  voltmeter  in  series.  If  the  cable  has 
no  break,  the  reading  of  the  voltmeter  should  show  approxi- 
mately the  same  deflection  as  when  the  battery  circuit  and 
voltmeter  alone  are  in  circuit. 

To  test  for  a  ground  the  cable  is  submerged  in  a  testing 
tank,  leaving  both  ends  out.  It  is  advisable,  when  practi- 
cable, to  extend  a  lead  from  one  of  the  operating  boards  of 
the  mining  casemate  to  the  cable  tank.  One  end  of  the  cable 
to  be  tested  is  connected  to  this  lead  and  the  test  made  as 
prescribed  for  "  insulation  test "  on  page  44.  The  condition 
of  a  multiple-conductor  cable  can  be  quickly  determined  by 
this  arrangement.  If  the  above  method  is  not  practicable,  a 
dry-cell  battery  with  a  mil-ammeter  and  protective  lamp  may 
be  installed  at  the  cable  tank ;  or,  in  place  of  the  mil-ammeter 
and  lamp,  a  voltmeter  placed  in  series  with  the  battery  and 
cable  may  be  used,  the  resistance  being  obtained  by  the  volt- 
meter method.  One  side  of  the  battery  should  be  grounded 
by  touching  the  cable  armor  or  by  using  an  earth  plate.  In 
actual  service,  cable  which  tests  under  1  megohm  should  not 
be  used ;  for  practice,  cable  under  10,000  ohms  should  not  be 
used.  If  post  power  is  used  as  a  source  of  energy  for  testing, 
the  system  should  be  free  from  grounds.  Care  should  be 
taken  to  have  the  cable  ends  and  battery  leads  free  from 
grounds  and  dry, 

Cables  are  raised  and  lowered  into  the  tank  by  means  of  a 
cable  yoke,  which  consists  of  an  11-foot  length  of  4  by  6 
inch  scantling,  with  three  hooks  on  the  lower  side  and  a 
ring  on  the  upper  side  at  the  center  for  hoisting.  The  lower 
hooks,  which  are  secured  to  the  scantling  by  a  bolt  and  ring, 
hook  into  the  lashing  on  the  cable.  Washers  are  placed 
under  the  bolt  heads  to  prevent  their  slipping  through  the 
holes. 


SUBMARINE    MINING.  51 

Swinging  or  traveling  cranes  with  triplex  blocks  are  used 
for  lowering  and  raising  cable  and  yoke. 

The  coils  of  single-conductor  cable  are  carried  aboard  the 
planter,  to  the  aft  deck,  by  the  cable  detail,  or  they  may  be 
lowered  onto  the  deck  by  means  of  the  cable  yoke  and  a  der- 
rick on  the  wharf.  The  cable  for  mine  No.  1  is  placed  on 
the  starboard  side  of  the  aft  deck  and  its  mine-cap  end  is 
carried  forward  on  the  cable  racks  close  to  the  mines.  The 
other  cables,  Nos.  2  to  9,  inclusive,  are  placed  in  succession 
on  the  starboard  side  in  the  same  manner.  The  cables,  Nos. 
19  to  10  are  placed  in  succession  on  the  port  side,  with  No.  19 
at  the  bottom.  The  coils  on  each  slide  are  placed  on  top  of 
each  other.  The  cable  should  be  removed  from  the  racks 
when  its  corresponding  mine  is  being  prepared  for  planting. 

At  the  same  time  the  other  apparatus  and  appliances  are 
carried  aboard  and  placed  forward,  the  proper  supply  on 
each  side.  The  anchors  are  placed  as  convenient  to  the 
forward  davits  as  possible. 

Finally,  the  loaded  mines  are  put  aboard.  If  they  contain 
dynamite  they  should  be  protected  from  the  direct  rays  of 
the  sun  by  being  covered  with  a  paulin. 

Preparing  mines  for  planting. — The  detail  on  each  side  of 
the  planter  prepares  a  mine  on  its  own  side.  The  loading 
wire  from  the  mine  is  cust  to  the  proper  length,  a  water-tight 
joint  is  made  with  the  single  conductor  of  the  corresponding 
cable,  and  the  Turk's-head  is  clamped  in  place,  care  being 
exercised  that  no  part  of  the  leading-in  wire  is  caught  under 
the  clamp.  The  cable  is  lashed  with  soft-drawn  copper  wire 
or  secured  by  clips  to  the  bails  just  above  the  ring. 

The  proper  mooring  rope  is  now  shackled  at  one  end  to 
an  anchor,  at  the  other  end  to  the  mine,  and  is  lashed  to  the 
mine  cable  with  soft- drawn  copper  wire  at  every  5  feet.  If 
automatic  anchors  be  used,  the  mooring  rope  is  shackled  to 
the  mine  after  the  anchor  and  mine  are  swung  outboard ;  the 
lashing  of  the  cable  to  the  mooring  rope  is  omitted. 

A  rope  for  raising  the  mine  is  cut  to  the  length  of  80  feet 
plus  the  depth  of  water.  One  end  is  attached  to  the  anchor 
by  an  anchor  knot  or  bowline,  the  other  to  the  mine  cable  by 


52  SUBMARINE   MINING. 

two  half  hitches  and  a  seizing  of  soft-drawn  copper  wire. 
It  should  not  be  secured  at  other  points. 

The  mine  buoys  have  attached  to  them  60  feet  of  £-inch 
rope,  which  is  marked  at  every  5  feet.  The  free  end  is 
slipped  through  the  maneuvering  ring  of  the  mine  and  tied 
to  the  buoy. 

When  planting  mines  for  practice,  marline  may  be  used 
to  seize  the  raising  rope  to  the  cable  and  to  lash  the  cable  to 
the  bail  and  mooring  rope. 

A  mousing  must  be  put  around  the  upper  hook  of  the 
differential  block  to  prevent  the  block  from  jumping  off  the 
hook  when  the  mine  or  anchor  is  tripped.  The  tripping 
hook  of  the  differential  block  on  the  forward  davit  is  attached 
to  the  anchor  and  it  is  hoisted  and  swung  outboard  clear  of 
the  rail.  The  mine  is  similarly  slung  from  the  after  davit  by 
its  maneuvering  ring  or  by  a  rope  sling  through  the  latter. 
Both  mine  and  anchor  are  lowered  as  close  to  the  water  as 
conditions  will  permit.  A  heaving  line  is  bent  onto  the  free 
end  of  the  mine  cable,  generally  by  means  of  a  clove  hitch 
and  two  half  hitches. 

The  aft  detail  now  removes  or  cuts  the  rope  lashings  of  the 
coil  of  the  corresponding  mine  cable.  A  detail  sees  that  the 
cable  and  raising  rope  are  held  on  the  gunwale  ready  for 
planting.  These  should  not  be  allowed  to  trail  in  the  water. 
A  man  'stands  near  the  mine  davit  ready  to  throw  the  mine 
buoy  clear  of  the  planter  when  the  mine  is  tripped.  (Fig.  13 
shows  the  mine  and  anchor  slung  for  planting  and  fig.  14 
shows  the  relative  position  of  the  various  parts  in  the  water. 
In  these  figures  the  cable  should  be  shown  as  lashed  to  the 
mooring  rope.) 

The  distribution-box  boat  should  precede  the  planter  to  the 
mine  field.  The  distribution-box  buoy,  to  which  the  anchor 
rope  is  fastened  by  a  bowline,  to  the  bight  of  which  the  rais- 
ing rope  is  secured,  is  taken  aboard  at  !the  bow,  if  the  tide  is 
coming  in  toward  the  box,  and  the  anchor  rope  is  made  fast. 
The  distribution  box  is  then  raised  by  its  raising  rope  and 
secured  in  the  stern.  The  boat  is  thus  anchored  fore  and  aft, 
perpendicular  to  the  line  of  mines,  with  its  bow  pointed 
toward  the  position  of  the  center  mine  of  the  group.  If  the 
tide  is  running  out  from  the  box,  the  buoy  should  be  taken 


SUBMARINE    MINING.  53 

in  at  the  stern,  the  boat  being  held  in  position  by  the  raising 
rope  of  the  distribution  box  and  then  by  the  multiple  cable. 
The  anchor  rope  is  finally  made  fast  in  the  bow.  During  the 
planting  of  mines  a  man  should  always  stand  ready  to 
slacken  away  on  the  anchor  rope  if  necessary. 

If  the  buoy  for  the  distribution  box  is  not  in  place,  the 
cable  must  be  underrun,  either  from  shore  or  from  a  buoy 
planted  for  this  purpose.  This  is  done  preferably  with  a 
yawl.  The  cable  is  raised,  taken  aboard,  and  placed  over  a 
roller  or  rowlock  in  the  stern.  The  cable  is  then  pulled  in 
over  the  stern  and  lowered  over  a  roller  or  rowlock  in  the 
bow.  If  the  planter  is  to  underrun  cable,  a  cathead  is  put 
in  place  and  a  snatch  block  is  lowered  by  a  raising  rope 
secured  to  a  hoisting  windlass.  The  cable  is  placed  in  the 
snatch  block  and  the  planter  moves  forward  slowly.  When 
it  is  desired  to  transfer  the  cable  to  a  small  boat  the  snatch 
block  is  lowered  into  the  boat  and  the  cable  removed. 

After  the  distribution-box  boat  has  secured  the  box  in 
position,  the  lid  is  removed  and  the  cable  is  tested  as  pre- 
scribed on  page  44.  A  signal  is  then  raised  to  indicate  to 
the  planter  that  the  distribution-box  boat  is  ready  for  the 
planting  of  mines. 

Planting  the  mines. — If  there  be  a  strong  tide,  the  mines 
should,  if  possible,  be  planted  at  such  time  that  the  planter, 
in  going  out  toward  the  line  of  mines,  moves  against  the  tide. 

The  planter  moves  but  and  passes  close  to  the  distribution- 
box  boat,  with  the  latter  to  port.  As  it  passes  slowly  by.  a 
heaving  line  is  thrown  by  a  man  forward  of  the  beam  to  the 
distribution-box  boat,  whose  party  immediately  hauls  in  the 
mine  cable,  bends  on  another  heaving  line,  and  lashes  the 
cable  to  the  boat.  It  is  desirable  to  have  a  second  heaving 
line  ready  in  case  the  first  one  fails.  If  the  water  be  rough 
the  cable  end  is  passed  to  the  boat  by  a  launch. 

The  planter  moves  forward  to  the  position  to  be  occupied 
by  mine  No.  10.  If  automatic  anchors  are  used,  the  distance 
weight  is  lowered  at  the  command  "  Lower  weight,"  given 
after  the  cable  is  secured  in  the  distribution-box  boat.  As 
the  planter  approaches  this  position  the  command  "  Get 


54  SUBMAKINE    MINING. 

ready  "  is  given.  As  the  forward  davit  comes  abreast  of  the 
position  of  No.  10  mine,  the  officer  in  charge  of  the  planting 
commands  "  Let  go  " ;  the  tripping  hook  of  the  mine  is  re- 
leased first  and  that  of  the  anchor  immediately  thereafter. 
The  mine  buoy,  cable,  and  raising  rope  are  then  thrown 
overboard. 

(Caution. — The  men  operating  the  tripping  hooks  must 
be  very  careful  that  they  stand  back  of  all  cable  and  rope,  so 
that  they  may  not  be  caught.  All  others  must  stand  clear.) 

The  planter  turns  so  that  the  stern  will  be  thrown  away 
from  the  planted  mine.  When  the  stern  is  clear  of  the  mine 
buoy  "All  clear"  is  signaled  from  the  stern. 

The  planter  then  executes  a  sweeping  circle  to  starboard, 
passes  to  the  rear,  and  comes  up  with  the  distribution-box 
boat  to  starboard.  As  it  moves  by,  the  free  end  of  mine 
cable  No.  9  is  passed  to  the  boat  and  secured  as  before.  The 
planter  moves  ahead  to  a  point  100  feet  to  the  left  of  mine 
No.  10,  and  as  it  crosses  the  line,  plants  mine  No.  9,  swings 
off  to  port,  circles  and  comes  up  from  the  rear  with  the  dis- 
tribution box  to  port,  and  so  on  alternately  until  all  the 
mines  are  planted. 

As  soon  as  a  mine  is  dropped  the  detail  for  that  side  of 
the  planter  prepares  another  for  planting.  There  is  ample 
time  to  do  this  while  the  vessel  is  turning  and  planting  the 
other  mine. 

Two  small  boats,  one  on  each  side  of  the  line,  work  as  fol- 
lows: As  soon  as  a  mine  is  dropped  the  boat  on  the  corre- 
sponding side  moves  to  it,  picks  up  the  buoy,  pulls  the  rope 
taut,  notes  the  submergence  of  the  mine,  transmits  the  data 
to  the  planter,  and  holds  up  an  oar  or  a  flag  in  prolongation 
of  the  buoy  rope.  The  observers  at  the  ends  of  the  base  line 
take  observations  on  this  marker  and  are  thus  able  to  plot 
the  position  of  the  mine  accurately.  This  process  is  repeated 
for  each  mine. 

These  boats  also  serve  as  guides  to  the  planter  in  dropping 
mines  by  holding  on  to  their  buoys  until  the  adjacent  mines 
are  planted.  With  automatic  anchors  the  line  may  not  be 
marked  otherwise  than  in  this  manner. 


SUBMARINE   MINING.  55 

After  the  mine  is  dropped,  the  members  of  the  distribution- 
box  boat  party  remove  the  lashing  from  the  cable,  insert  the 
Turk's- head  in  the  proper  slot,  make  a  temporary  joint  be- 
tween it  and  the  corresponding  conductor  of  the  multiple 
cable,  and  telephone  to  the  casemate  operator.  The  latter 
opens  all  the  power  switches  on  the  corresponding  operating 
board,  closes  switch  No.  7  up  (this  throws  D.  C.  power  on 
the  mil-ammeter  lead) ,  and  then  plugs  in  on  the  upper  jaw  of 
the  power  switch  of  the  mine  under  test.  If  the  D.  C.  volt- 
age be  110,  the  mil- ammeter  should  read  about  40  mil- 
amperes  ;  if  the  voltage  be  80,  the  reading  should  be  about  30. 
If  this  test  be  satisfactory,  the  joint  is  made  permanent. 

For  the  last  mine  the  telephones  are  removed  from  the 
corresponding  conductor,  a  temporary  joint  is  made  in  the 
boat,  and  the  test  made  as  above.  By  arrangement  with  the 
casemate  operator  the  mine  is  left  on  two  minutes  for  test. 
At  the  end  of  this  time  the  joint  is  opened  and  the  telephones 
put  back.  If  the  casemate  operator  reports  the  test  satisfac- 
tory, the  telephones  are  again  removed  and  a  permanent 
joint  is  made. 

When  the  last  joint  has  been  made,  the  distribution  box  is 
closed  and  the  raising  rope  fastened  to  its  lid.  The  box  is 
then  lowered.  This  is  done  by  the  distribution-box  boat  if 
it  is  provided  with  the  necessary  davit  and  power,  otherwise 
it  is  done  by  the  planter.  Generally  the  anchor  rope  is  made 
fast  to  a  buoy  by  a  bowline,  and  the  raising  rope  of  the  dis- 
tribution box  is  secured  to  the  bight  of  the  bowline. 

After  the  distribution  box  is  lowered  all  buoys  are  re- 
moved except  that  for  the  box,  and  such  others  as  it  may  be 
desired  to  place  for  marking  the  ends  of  lines.  The  mark- 
ing boats  may  remove  the  mine  buoys  as  they  work,  provided 
they  are  notified  from  the  mine  commander's  station  that 
proper  observations  for  plotting  have  been  obtained.  Such 
notification  is  usually  sent  by  telephone  to  the  distribution- 
box  boat. 

In  time  of  war  decoy  buoys  judiciously  placed  would  be 
very  useful  in  deceiving  the  enemy. 


CHAPTER  VI. 
TESTS  OF  MINES  AND  APPARATUS. 

After  the  mines  have  been  planted  the  following  tests  are 
made  daily,  or  more  frequently  if  need  be,  the  results  being 
recorded  carefully  on  the  form  given  at  the  end  of  the 
chapter.  (Note :  This  applies  also  to  such  test  mines  as  may 
be  kept  planted  for  purposes  of  observation  and  instruction. ) 

Caution. — If  A.  C.  power  be  supplied  from  the  casemate 
motor-generator,  there  is  no  possibility  of  accidental  firing 
of  mines  if  the  motor-generator  is  not  running;  and  when 
it  is  running  the  chance  is  remote,  since  it  would  require  the 
committing  of  three  blunders.  However,  the  following  pre- 
cautions must  be  enforced  rigidly: 

(a)  Never  start  the  motor- generator  during  the  planting 
of  mines  nor  when  any  friendly  vessels  are  in  the  neighbor- 
hood of  the  mine  field. 

(b)  Before  starting  the  motor-generator  for  testing  it,  see 
that  all  automatic  switches  are  up,  all  firing  switches  open, 
and  the  A.  G .  operating  switch  (No.  8  of  the  power  panel} 
open. 

1.  Test  of  the  D.  C.  voltage. — Plug  in  at  the  proper  recep- 
tacle and  read  the  voltmeter. 

2.  Test  of  the  A.  C.  voltage. — Caution. — First  see  that  all 
automatic  switches  are  up,  that  the  firing  switches  are  open, 
and  that  the  A.  C.  operating  switch  No.  8  is  open. 

Close  switch  No.  4  up;  close  starting  switch  of  moitor- 
generator,  and  when  the  latter  has  attained  its  full  speed 
close  switch  No.  9  up ;  plug  in  at  the  proper  receptacle,  and 
read  the  voltmeter.  When  the  source  of  power  is  the  storage 
battery,  the  battery  rheostat  should  be  adjusted  until  the  A.  C. 
voltage  is  500  or  above;  when  the  casemate  generator  is  used, 
its  field  rheostat  should  be  adjusted  for  the  same  purpose. 
56 


SUBMARINE    MINING.  57 

3.  Test  of  the  mines. — Leakage  in  mine  circuits  will  be  indi- 
cated automatically  by  an  increased  brightness  of  the  green 
lamp  on  the  signal  block;  an  excessive  leakage  in  any  mine 
circuit  may  cause  the  automatic  switch  to  trip. 

However,  each  mine  should  be  tested  separately,  as  fol- 
lows: 

With  the  D.  C.  on  the  D.  C.  busses  of  the  power  panel, 
close  switch  7  up,  open  the  power  switch  on  the  mine  block 
of  the  mine  circuit  to  be  tested,  and  put  the  M-AM  "  plug  " 
on  the  upper  point  of  the  power  switch.  If  the  automatic 
switch  falls,  adjust  the  solenoid  or  hold  the  switch  up  while 
testing  the  circuit,  otherwise  the  reading  obtained  will  be 
that  of  the  red  lamp  and  bell  circuit.  These  operations 
put  the  mil-ammeter  and  its  protective  lamp  in  series  with 
the  mine  circuit. 

The  circuit  is  as  follows :  From  the  negative  D.  C.  bus  on 
the  power  panel,  to  switch  7  closed  up,  through  the  mil- 
ammeter  and  its  protective  lamp,  to  the  terminal  bar,  to  the 
M-AM  lead,  to  the  plug,  to  the  upper  point  of  the  power 
switch  P,  through  the  solenoid,  to  the  middle  of  the  testing 
switch  T,  to  the  upper  point  of  same,  to  the  upper  point  of 
the  automatic  switch,  to  the  middle  of  same,  to  the  mine 
switch,  through  same,  to  the  terminal  bar,  through  the  19- 
conductor  and  the  single-conductor  cables,  to  the  mine  trans- 
former primary,  to  the  mine  case,  to  ground,  to  the  D.  C. 
"earth"  terminal  on  the  power  panel,  to  switch  7,  and  to 
the  positive  D.  C.  bus  on  the  power  panel. 

With  from  80  to  110  volts  these  readings  should  normally 
be  between  30  and  40  mil- amperes.  A  mine  may  be  fired  if 
the  reading  with  80  volts  is  between  14  and  120  mil-amperes. 
These  limits  increase  with  the  testing  voltage.  If  the  mine 
tests  within  the  firing  limits,  the  solenoid  should  be  adjusted 
if  the  current  is  above  its  normal  setting  (0.075  amperes). 
If  the  test  indicates  that  the  mine  can  not  be  fired,  the  mine 
switch  should  be  opened. 

4.  Test  of  the  automatic  switch,  red  lamp,  and  bell. — Throw 
the  D.  C.  power  on  the  busses  of  the  operating  board  by 
closing  switch  3  up.     Open  the  bell  switch.     Next  close  the 
testing  switch  down  on  the  mine  block  under  test.    The  red 


58  SUBMARINE    MINING. 

lamp  should  glow  and  the  corresponding  automatic  switch 
trip.  (For  circuit  see  fig.  18.)  Now  close  the  bell  switch, 
throwing  the  bell  in  parallel  with  the  red  lamp;  the  bell 
should  ring.  Next  open  the  bell  switch  and  repeat  the  test 
for  each  mine  block  in  turn. 

5.  Test  of  the  alternating  circuit. — This  circuit  is  tested  with 
D.  C.,  as  follows:  Connect  the  A.  C.  and  D.  C.  jaws  on  the 
master  block  witlt  a  jumper,  open  the  power  switches,  close 
switches  3,  8,  and  9  up  on  the  power  panel.  The  green  and 
white  lamps  of  the  operating  board  under  test  should  glow. 
A  break  or  an  excessive  resistance  in  the  casemate  grounds, 
or  elsewhere  in  the  circuit,  will  be  indicated  by  the  lamps  not 
glowing,  or  glowing  dimly. 

The  circuit  is  as  follows:  From  the  negative  D.  C.  bus  on 
the  power  panel,  to  switch  3,  to  the  "  operating  board  "  ter- 
minal, to  the  D.  C.  lead,  to  the  D.  C.  post  on  the  signal  block, 
through  the  green  lamp,  to  the  D.  C.  jaw  on  the  master 
block,  through  the  jumper,  to  the  A.  C.  jaw  on  the  master 
block,  through  the  white  lamp  and  resistance  in  parallel, 
to  the  A.  C.  post  on  the  signal  block,  to  the  A.  C.  lead,  to 
the  A.  C.  "  operating  board  "  terminal,  to  switch  8,  to  the 
A.  C.  bus,  to  switch  9,  to  the  casemate  transformer  second- 
ary, back  to  switch  9,  to  the  other  A.  C.  bus,  back  to  switch 
8,  to  the  A.  C.  earth,  through  ground,  to  the  D.  C.  earth,  to 
switch  3,  and  to  the  positive  D.  C.  bus  on  the  power  panel. 
With  this  circuit  on,  remove  the  90-ohm  resistance  in  parallel 
with  the  white  lamp ;  the  white  lamp  should  glow  more 
brightly,  indicating  continuity  of  circuit  through  the  resist- 
ance as  well  as  the  white  lamp. 

It  will  be  observed  that  the  above  test  is  for  only  a  part 
of  the  A.  C.  circuit.  To  test  the  firing  switch  and  the  lower 
contact  of  the  automatic  switch,  open  switches  3,  8,  and  9, 
close  7  up,  remove  the  jumper,  put  the  M-AM  "  plug  "  on 
the  A.  C.  jaw  on  the  master  block,  close  the  firing  switch,  and 
trip  in  turn  each  automatic  switch  by  raising  the  corre- 
sponding knob  on  the  solenoid  and  observe  the  reading  of 
the  mil-ammeter.  Close  each  automatic  switch  up  before 
tripping  the  next  one. 


SUBMAKINE    MINING.  59 

The  mil- ammeter  reading  should  be  from  30  to  40  mil- 
amperes,  indicating  a  circuit  through  the  firing  switch  and 
the  automatic  switch.  The  circuit  is  as  follows:  From  the 
negative  D.  C.  bus  on  the  power  panel,  to  switch  7  closed  up, 
through  the  mil- ammeter  and  its  protective  lamp,  to  the 
operating  board  terminal,  to  the  M-AM  lead,  to  the  "  plug," 
to  the  A.  C.  jaw  on  the  master  block,  through  the  firing 
switch  F.  S.,  to  the  A.  C.  bus  on  the  operating  board,  to  the 
lower  point  of  the  automatic  switch  which  was  tripped,  to 
the  middle  of  same,  to  the  mine  switch,  through  the  same, 
to  the  terminal  bar,  through  the  19-conductor  and  the  single- 
conductor  cables,  to  the  mine  transformer  primary,  to  the 
mine  case,  to  ground,  to  the  D.  C.  "  earth  "  post  on  the  power 
panel,  to  switch  7,  to  the  positive  D.  C.  bus  on  the  power 
panel; 

6.  Test  of  the  delivery  of  the  A.  C.  power  to  the  operating 
board. — See  that  all  the  automatic  switches  of  the  operating 
boards  are  up  and  all  the  firing  switches  of  the  master  blocks 
open.    Close  switches  4  and  9  up  (or  down)  and  8  down ;  close 
the  testing  switch  T.  S.  on  the  master  block.     The  white 
lamp  should  glow  and  the  A.  C.  bus-bar  voltage  should  drop 
appreciably. 

The  circuit  is  as  follows :  From  the  A.  C.  bus  on  the  power 
panel,  to  the  lower  right  terminal  of  switch  8,  to  the  "  oper- 
ating board  "  terminal,  to  the  A.  C.  lead,  to  the  A.  C.  post  on 
the  signal  block,  to  the  white  lamp  and  the  resistance  in  par- 
allel, to  the  A.  C.  jaw  on  the  master  block,  to  the  testing 
switch  T.  S.,  to  the  "  earth  "  post  on  the  signal  block,  to 
the  earth  lead,  to  the  D.  C.  earth,  through  earth,  to  the  A.  C. 
earth  terminal  on  the  power  panel,  through  the  choke  coil, 
to  switch  8,  to  the  other  A.  C.  bus  on  the  power  panel. 

In  this  test  it  is  imperative  to  see  that  all  the  automatic 
switches  are  up  and  all  the  firing  switches  are  open. 

7.  Test  of  the  power. — Insert  two  fuses  in  multiple  across 
the  fuse  leads  from  the  power  panel.     Put  the  fuses  in  a  place 
prepared  for  the  purpose  outside  of  the  casemate,  so  that 
there  will  be  no  danger  from  flying  fragments.     With  all  the 
switches  on  the  power  panel  open,  all  the  automatic  switches 


60  SUBMARINE    MINING. 

up,  and  the  firing  switches  on  the  master  blocks  open,  ener- 
gize the  D.  C.  busses  of  the  power  panel,  close  switch  No.  4 
up  (or  down),  and  close  the  starting  switch;  close  switch 
No.  9  up  (or  down)  ;  close  switch  No.  12  up  (which  connects 
the  mine  transformer  secondary  to  the  fuses)  ;  and,  finally, 
close  switch  No.  11  up  (which  throws  the  A.  C.  power  on  the 
mine  transformer  primary) .  The  fuses  should  explode. 

If  fuses  are  not  available  for  this  test,  a  low-voltage  lamp 
or  a  short  piece  of  fine  wire  may  be  heated  to  incandescence. 

8.  Test  of  grounds. —  (a)  "  Separate  "  grounds  shall  be  made 
for  the  A.  C.  power  and  the  D.  C.  power  on  the  power  panel. 
The  word  "  separate  "  as  here  used  means  actual  connection 
to  earth  without  metallic  contact  of  the  earth  leads.  A 
convenient  method  of  making  a  ground  is  to  connect  to  the 
armor  of  a  cable  running  to  salt  water,  a  bond  being  made 
in  case  the  armor  of  the  cable  in  the  casemate  does  not  reach 
water  before  a  joint  is  made.  If  a  cable  armor  is  used 
for  one  ground,  the  other  ground  lead  must  go  to  earth  with- 
out contact  with  that  armor.  This  may  be  accomplished  by 
using  the  conductors  of  a  cable,  the  ends  of  which  are 
grounded  to  an  earth  plate  in  'salt  water. 

(6)  Neither  of  the  grounds  made  should  have  more  than 
10  ohms  resistance.  To  verify  this,  tests  should  be  made 
as  follows : 

Close  the  double  circuit  breaker ;  close  switch  7  up  and  plug 
the  extension  cord  of  the  mil-ammeter  lead  of  the  power 
panel  on  the  upper  left-hand  terminal  of  switch  8,  the  mil- 
ammeter  extension  cords  for  the  operating  boards  being  dis- 
connected. 

Ascertain  the  voltage  across  the  mil- ammeter  and  lamp, 
and  across  the  bus  bars.  Read  the  mil- ammeter. 

From  these  readings  the  combined  resistance  of  the  grounds 
can  be  determined. 

A  table  or  chart  may  be  prepared  giving  the  resistances  for 
various  testing  voltages  and  mil-ammeter  readings. 


SUBMAKINE    MINING. 

Form  for  record -of  tests,  Group  No. 


61 


I 

No. 

£ 

5 

": 

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Z* 

J? 

C.  on  A.  C. 
.  S.  closed. 

SJ? 

i! 

M 

D.  C.  on  A.  C. 

F.  S.  closed. 

f 

Auto,  switch 
lamp  &  bell. 

D.  C.  on  A.  C. 
F.  S.  closed. 

a, 
= 

- 

Auto,  switch 
lamp  &  bell. 

D.  O.  on  A.  C. 
F.  S.  closed. 

Mil.  amp. 

Auto,  switch 
lamp  &  bell. 

-  _• 
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m 

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Auto,  switch 
lamp  &  bell. 

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Re- 
marks. 

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12 
13 

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14 

15 

- 

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16 

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17 

18 
19 

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D.  C.  on  A.  C. 
F.  S.  open. 

D.  C.  volts  .... 

—  

A.  C.  volts  

Fuses,  fired  

Delivery  of  A. 
C.  power  to 
the  Op.  Bd. 



Grounds. 

Remarks. 

CHAPTER  VII. 
TAKING  UP  MINES. 

Mines  should  be  raised  in  the  reverse  order  from  that  in 
which  they  were  planted  if  the  conditions  of  wind  and  tide 
are  favorable.  With  a  cross  tide  or  a  strong  cross  wind,  the 
mines  should  be  taken  up  in  regular  order  from  one  side  so 
that  the  planter  will  not  drift  onto  the  mine  field. 

A  yawl  or  launch  takes  position  at  the  outer  mine  on  each 
side.  The  mine-buoy  rope  is  hauled  up  taut  in  order  to 
locate  the  exact  position  of  the  mine.  The  boat  holds  fast 
until  directed  from  the  planter  to  let  go.  While  the  anchor 
and  mine  are  being  taken  aboard  the  planter,  the  boat 
remains  off  the  bow  to  render  assistance  if  necessary. 

The  distribution  box  is  raised  by  underrunning  the  mul- 
tiple cable,  or  by  means  of  its  raising  rope  if  the  buoy  has 
not  been  removed.  The  box  is  taken  aboard  the  distribution- 
box  boat,  the  lid  is  removed,  and  the  mine  cables,  in  turn, 
disconnected  from  the  multiple  cable.  The  planter  passes 
close  to  the  distribution-box  boat.  A  heaving  line  which  has 
been  made  fast  to  the  outer  mine  cable  is  thrown  to  the  bow 
of  the  planter.  If  this  should  fail,  a  man  throws  a  heaving 
line  from  the  bow  of  the  planter.  If  the  conditions  be  unfa- 
vorable for  passing  a  heaving  line,  a  launch  may  carry  the 
line  to  the  planter.  The  heaving  line  attached  to  the  cable  is 
hauled  aboard  and  the  cable  placed  over  the  cathead.  The 
planter  then  proceeds  to  underrun  the  cable.  If  the  water 
be  shallow,  the  cable  is  carried  through  a  snatchblock  to  the 
aft  deck  and  coiled,  or  it  may  be  carried  to  a  cable  reel  for- 
ward. If  the  water  be  deep,  or  the  cable  can  not  be  raised 
easily  by  hand,  it  is  carried  through  a  snatchblock  to  the 
drum  of  a  hoisting  windlass  and  coiled  as  before  mentioned. 
62 


SUBMARINE   MINING.  63 

(If  placed  on  a  cable  reel,  the  ends  should  be  insulated  and 
tagged.  Mine  cables  Nos.  1  to  9  should  be  placed  on  one  reel 
and  Nos.  10  to  19  on  another,  both  reels  being  carefully 
marked.)  When  the  raising  rope  is  reached,  it  is  carried 
with  the  cable  over  the  cathead.  The  bight  of  the  rope  is 
hauled  in  quickly,  carried  through  a  snatchblock,  and  a  few 
turns  taken  on  the  drum  of  a  hoisting  windlass.  The  rope  is 
untied  from  the  cable  as  soon  as  possible.  If  there  be  danger 
of  losing  the  rope,  it  should  be  made  fast  at  once.  The 
anchor  is  raised  until  within  a  few  feet  of  the  cathead.  It 
is  lifted  aboard  by  means  of  the  boom,  or  by  the  differential 
block  on  the  anchor  davit. 

At  the  same  time  a  man  is  sent  over  the  side  of  the  planter 
near  the  mine  davit  (a  rope  ladder  may  be  used)  to  secure 
the  hook  of  the  differential  block  in  the  sling  attached  to  the 
maneuvering  ring  of  the  mine  when  it  comes  to  the  surface. 
To  bring  the  mine  to  the  proper  place  to  accomplish  this,  a 
man  should  be  ready  to  secure  the  mine-buoy  rope  with  a 
boathook;  other  men  should  be  ready  to  pull  the  mine  for- 
ward, if  necessary,  by  means  of  the  cable.  The  mine  is  raised 
by  the  differential  block  of  the  mine  davit.  It  may  be  raised 
by  the  boom  and  fall ;  or  by  means  of  a  tackle  secured  to  the 
mine  davit,  the  end  of  the  rope  running  through  a  snatch- 
block  to  the  drum  of  a  windlass.  The  distance  weight  of  the 
automatic  anchor  may  be  raised  by  the  fall  of  the  boom,  or 
by  an  improvised  tackle.  An  eye  should  be  made  in  the 
distance  rope  for  this  purpose. 

If  the  end  of  the  cable  is  lost,  the  work  may  proceed  as 
follows:  The  planter  moves  out  to  the  mine  if  its  buoy  is 
still  in  place.  A  sling  made  of  raising  rope  may  be  thrown 
over  the  mine,  or  two  raising  ropes  are  tied  together  and 
one  end  is  passed  to  a  launch  which  moves  around  the  mine 
and  brings  the  end,  back  to  the  planter.  Both  ends  are 
placed  over  the  cathead,  through  a  snatchblock,  and  around 
the  drum  of  a  hoisting  windlass.  The  mine  is  hoisted,  bail 
up,  until  near  the  cathead.  It  can  then  be  transferred  to  the 
anchor  davit.  The  mine  cable  is  pulled  in  until  the  raising 
rope  is  reached.  The  work  then  proceeds  as  before.  If  the 
11003°— 12 6 


64  SUBMARINE   MINING. 

mine  buoy  has  been  removed,  a  yawl  may  drag  for  the  cable 
with  a  grappling  iron.  If  the  raising  rope  should  break  or 
be  lost,  the  mine  may  be  raised  as  mentioned  above,  except 
that  the  mine  must  be  transferred  to  the  fall  of  the  boom  and 
the  anchor  raised  by  means  of  its  mooring  rope,  or  the  mine 
may  be  transferred  to  the  anchor  davit,  as  before,  and  a  rais- 
ing rope  made  fast  to  the  mooring  rope  of  the  anchor  and 
carried  over  the  cathead,  through  a  snatchblock,  to  a  hoisting 
windlass.  The  mine,  as  soon  as  the  strain  is  taken  up  by  the 
raising  rope,  is  unshackled.  The  anchor  is  then  taken  aboard 
in  the  usual  manner. 

As  soon  as  the  mines  are  taken  aboard  they  are  discon- 
nected, the  ropes  are  coiled,  and  all  materiel  placed  so  as  not 
to  interfere  with  subsequent  work.  As  soon  as  the  materiel 
is  unloaded  on  the  wharf  it  should  be  cleaned  thoroughly  and 
stored. 

If  the  multiple  cable  is  to  be  left  down,  the  ends  of  the 
conductors  are  insulated,  the  lid  replaced,  and  the  box  low- 
ered by  means  of  a  raising  rope,  the  end  of  which  is  made 
fast  to  the  bight  of  the  bowline  of  the  anchor  rope. 

If  the  multiple  cable  is  to  be  taken  up,  the  end  is  passed  to 
the  planter,  run  through  a  large  snatchblock  on  the  bow,  and 
coiled  on  a  cable  reel  as  it  is  raised.  Whenever  a  multiple 
cable  is  coiled  on  a  reel  it  should  be  secured  so  that  both  ends 
will  be  available  for  test  when  the  cable  is  stored. 

Unloading  mines. — Should  any  of  the  mines  be  loaded  with 
dynamite  the  utmost  care  must  be  exercised  in  unloading 
them.  (See  p.  76.)  Some  contrivance  must  be  rigged  up 
so  that  the  first  few  turns  of  the  compound  plug  may  be 
accomplished  by  the  operator  at  a  distance,  as  there  is  great 
liability  of  explosion,  due  to  leakage  of  nitroglycerin  into 
the  screw  threads.  After  the  compound  plug  is  removed  the 
precautions  to  be  observed  are  given  in  Appendix  No.  1. 

Should  the  mine  be  loaded  with  guncotton  or  trotol,  no 
danger  is  to  be  apprehended  in  unloading;  the  usual  pre- 
cautions in  handling  high  explosives  must,  of  course,  be 
observed. 


CHAPTER  VIII. 
THE  MINE  COMMAND. 

A  mine  command  consists  of  the  mine  groups  and  rapid- 
fire  batteries  specifically  assigned  for  their  protection,  which 
are  controlled  by  a  single  individual. 

The  mine  commander  is  in  direct  command  of  the  ele- 
ments of  the  mine  defense  during  drill  and  action.  His 
station  is  at  the  mine  primary,  which  is  connected  by  tele- 
phone to  the  battle  commander's  station.  He  bears  the  same 
relation  to  the  battle  commander  as  do  the  fire  commanders, 
and  his  duties  are  similar  to  theirs. 

The  mine  commander  is  responsible  that  the  property 
officer  requests  for  all  materiel  necessary  to  carry  out  the 
approved  scheme  for  mining  the  harbor;  he  is  responsible, 
further,  that  the  property  officer  keeps  this  materiel  in  proper 
condition  for  immediate  service. 

The  senior  company  officer  of  the  mine  command  is  the 
property  officer  and  obtains  from  the  district  artillery  engi- 
neer all  necessary  materiel  for  the  mine  defense.  He  has 
direct  charge  of  the  storeroom,  cable  tanks,  loading  room, 
wharves,  boats,  boathouses,  and  mining  casemate.  The  per- 
sonnel of  the  mine  companies  are  subject  to  his  orders  for 
service  in  connection  with  caring  for  and  maintaining  this 
materiel. 

The  officers  of  the  companies  of  the  mine  command  will 
be  assigned  by  the  mine  commander  in  accordance  with 
their  special  fitness. 

The  enlisted  personnel  of  mine  companies  will  be  divided 
into  sections,  detachments,  and  details,  as  follows: 

(a)  Fire-control  and  power  section. 

(b)  Planting  and  loading  section. 

(c)  Gun  and  ammunition  sections. 

(d)  Reserve  section. 

65 


66  SUBMARINE   MINING. 

These  will  be  subdivided  as  follows : 

(a)   Fire-control  and  power  section: 

1.  Observing  detachment — 

a.  W  detail. 
6.  M"  detail. 
c.  M'"  detail. 

2.  Plotting  detachment — 

a.  Plotting-board  detail. 
&.  Communication  detail. 

3.  Power  detachment — 

a.  Casemate  detail. 
6.  Searchlight  detail. 
(I)  Planting  and  loading  section: 

1.  Planting  detachment — 

a.  Planter  detail. 

&.  Small-boat  details. 

2.  Loading  detachment — 

a.  Loading-room  detail. 
6.  Explosive  detail, 
c.  Cable  detail. 

(c)  Gun  and  ammunition  section: 

a.  Gun  details. 

6.  Projectile  detail. 

c.  Powder  detail. 

( d )  Reserve  section  :  As  required. 

In  each  company  assigned  to  the  mine  defense,  a  perma- 
nent manning  table  will  be  made  out  and  always  kept  up  to 
date.  A  copy  of  this  manning  table  will  be  posted  in  the 
mine  commander's  station.  In  addition,  a  copy  of  such  por- 
tion of  this  table  as  pertains  to  any  particular  station  will 
be  posted  therein. 

Plotting  board. — The  plotting  board  differs  from  that  used 
for  guns  in  that  it  requires  no  gun  arm  and  corresponding 
attachments.  Furthermore,  since  the  distance  at  which  mines 
are  planted  will  in  general  be  small,  the  board,  without  any 
change  in  size,  may  be  used  with  a  much  larger  scale,  say,  150 
yards  or  even  100  yards  to  the  inch,  and  the  arms  graduated 
accordingly. 

The  stations  are  manned  during  the  planting  of  mines  and 
the  location  of  distribution  boxes,  as  well  as  during  opera- 
tions. 


105-  -105 


120 120 

125 125 


ISO 150 

155 155 

I60-M60 
165 
ITO-f-  ITO 
175 ITS 


FIG.  15.— PREDICTION   RULER. 


SUBMARINE   MINING.  67 

For  planting  buoys  signals  may  be  made  from  the  pri- 
mary, from  the  secondary,  or  from  both,  as  conditions  war- 
rant. 

Observations  are  taken  on  each  mine  as  planted,  the  data 
are  recorded,  and  the  position  of  each  mine  is  plotted. 

During  operations  vessels  may  be  tracked  by  the  vertical 
or  by  the  horizontal  method  of  position  finding.  If  by  the 
former,  either  the  command  "  Fire  "  may  be  given  when 
the  vessel  is  on  the  cross  wires  of  the  instrument  set  at  the 
range  and  azimuth  of  a  mine,  or  the  time  from  any  point  to 
the  instant  of  passing  over  a  mine  may  be  found  by  means 
of  the  prediction  ruler  (see  below)  and  the  command  "  Fire  " 
be  given  at  the  proper  instant,  as  indicated  by  the  stop 
watch.  For  the  horizontal  base  system  the  latter  method 
must  be  used. 

Prediction  ruler  (fig.  15). — This  is  a  10-inch  white  celluloid 
slide  rule  with  a  beveled  edge.  The  slide  is  graduated  in 
"  Yards  in  15  seconds,"  and  on  the  left  and  right  of  the  run- 
way, respectively :  are  a  "  Fire  at  time  "  and  a  "  Yards  to 
mine  "  scales.  The  beveled  edge  is  graduated  from  the  cen- 
ter outward  in  both  directions  with  "  0  "  in  the  center  of  the 
scale  and  "500"  at  either  end.  Each  50  and  100  has  its 
value  engraved  on  the  scale. 

Method  of  using. — Plot  the  position  of  the  target  for  a  15- 
second  interval.  With  the  beveled  edge  find  the  distance  the 
target  has  passed  over  during  the  interval;  and  also  deter- 
mine the  distance  from  the  last  plotted  position  to  the  mine. 
Move  the  slide  until  the  graduation  corresponding  to  the 
"  Yards  in  15  seconds "  is  opposite  the  graduation  corre- 
sponding to  the  "  Yards  to  mine,"  and  read  the  "  Fire  at 
time  "  scale  opposite  the  arrow  on  the  slide.  The  reading 
will  be  the  number  of  seconds  from  the  last  plotted  position 
to  the  mine  which  the  vessel  is  approaching.  A  stop  watch 
is  started  at  the  time  of  the  last  observation  on  the  target, 
and  at  the  expiration  of  the  time  obtained  from  the  "  Fire 
at  time  "  scale  the  command  "  Fire  "  may  be  given. 

Observation  firing. — The  mine  commander's  station  is  con- 
nected with  the  casemate  by  telephone.  At  the  command 
"  Observation  firing  "  sent  to  the  casemate,  the  casemate  oper- 


68  SUBMAKINE   MINING. 

ator  will  see  that  all  automatic  switches  are  up,  and  that  all 
•firing  switches  are  open.  He  will  then  close  the  double 
circuit  breaker,  and  switches  4  and  9,  which  will  energize  the 

busses  of  the  power  panel.  At  the  command  "  Group , 

mine  -  — ,"  the  operator  will  close  switches  3  and  8  on  the 
power  panel,  thereby  putting  both  D.  C.  and  A.  C.  power  on 
the  operating  boards.  At  the  command  "  Ready,"  given 
from  the  mine  commander's  station  at  the  proper  time,  the 
operator  will  stand  ready  to  trip  the  corresponding  auto- 
matic switch.  At  the  command  "  Fire  "  the  automatic  switch 
will  be  tripped  and  the  firing  switch  will  be  closed.  Without 
delay,  after  the  mine  is  fired,  the  firing  switch  and  the  power 
switch  will  be  opened,  the  automatic  switch  closed  up,  and 
the  mine  switch  opened  on  the  mine  block. 

If  the  mine  is  struck  before  the  command  "  Fire  "  is  given, 
the  automatic  switch  will  fall,  and  the  mine  should  be  fired 
by  closing  the  firing  switch  unless  there  are  positive  orders 
to  the  contrary. 

Contact  firing. — For  contact  firing  the  mine  system  will  be 
set  so  thalt  a  signal  will  be  sent  to  the  casemate  and  the  mine 
will  be  fired  when  the  latter  is  struck  by  a  passing  vessel. 
This  is  the  normal  method  of  firing  in  actual  service.  At  the 
command  "  Contact  firing,"  which  may  be  given  for  all 
groups,  or  certain  individual  ones,  the  casemate  operator  will 
see  that  all  automatic  switches  are  up,  power  and  mine 
switches  closed,  and  firing  switches  open;  he  will  then  close 
the  double  circuit  breaker,  and  switches  4,  9,  3,  and  8  on  the 
power  panel.  This  puts  both  D.  C.  and  A.  C.  on  the  operat- 
ing boards.  He  will  then  close  the  firing  switches  on  all  the 
boards  or  on  such  as  may  have  been  indicated.  When  a  mine 
has  been  fired,  the  corresponding  mine  block  will  be  cut  out. 

If  it  is  desired  to  delay  the  firing  of  a  mine  after  being 
struck,  the  command  "  Delayed  contact  firing  "  is  given.  The 
operations  are  the  same  as  for  contact  firing  except  that  the 
firing  switch  is  closed  by  the  operator  a  short  time  after  the 
mine  has  been  struck  or  when  directed  to  do  so.  After 
the  mine  has  been  fired  the  firing  switch  will  be  opened,  and 
the  corresponding  mine  block  will  be  cut  out. 


APPENDIX  NO.  1. 
EXPLOSIVES. 

The  latest  adopted  explosive  for  submarine  mines  is 
trinitrotoluol,  also  called  trotol.  The  commercial  names  for 
this  explosive  are  trinol,  trotyl,  and  triton. 

Wet  guncotton  is  used  extensively  for  submarine  mines 
and  in  emergency  other  commercial  high  explosives  may  be 
employed,  preferably  dynamite. 

Trotol  is  a  fine  crystalline  yellow  powder,  much  resembling 
brown  sugar.  It  is  manufactured  by  nitrating  toluol.  It 
is  very  insensitive  to  shock  or  friction,  insoluble  in  water, 
very  stable  in  storage,  and  very  powerful  when  detonated. 
Its  melting  point  is  about  81°  C.,  its  ignition  point  is  about 
197°  C.?  its  specific  gravity  in  powdered  form  is  about  1.55 ; 
it  has  no  dangerous  chemical  action  on  metals. 

The  priming  charge  is  a  fuse  can  full  of  crystalline  trotol. 

Trotol  is  supplied  in  wooden  boxes  doubly  lined  with  wax 
paper,  each  box  containing  about  50  pounds  of  explosive. 
The  date  of  receipt  at  the  post  and  the  name  of  the  explosive 
shall  be  painted  on  each  box.  The  boxes  should  be  stored  in 
tiers  with  the  marked  end  out,  the  bottom  tier  resting  on 
skids.  The  explosive  is  not  dangerous  to  handle,  but  the 
same  care  should  be  observed  in  storing  and  handling  as  with 
other  high  explosives.  It  should  be  stored  in  a  perfectly  dry 
place,  preferably  in  a  magazine.  If  it  is  impracticable  to 
store  in  a  magazine,  the  explosive  may  be  stored  in  the  driest 
place  available  where  it  is  protected  thoroughly  from  all  fire 
risks.  If  from  any  cause  the  boxes  of  explosive  are  wet  and 
there  is  reasonable  assurance  that  the  interior  has  become 
wet,  a  box  should  be  selected  and  opened.  If  the  interior  is 
wet,  a  full  report  of  the  circumstances  shall  be  made  to  the 
War  Department.  Boxes  should  be  opened  and  the  contents 
dried  in  open  air  out  of  the  direct  rays  of  the  sun. 

69 


70  SUBMARINE   MINING. 

Trotol  may  be  stored  with  wet  guncotton,  explosive  D,  and 
dynamite. 

Inspection  at  posts  will  be  limited  to  seeing  that  the  rules 
for  storage  and  care  are  strictly  observed.  Technical  in- 
spections will  be  made,  when  required,  by  the  Ordnance 
Department. 

Wet  guncotton  in  the  form  of  compressed  cakes  is  supplied 
in  boxes  lined  with  zinc,  the  lid  being  screwed  down  upon  a 
rubber  gasket  so  as  to  prevent  the  loss  of  water  by  evapora- 
tion. Each  box  contains  100  pounds  of  dry  guncotton. 
In  the  lid  is  a  small  flush  cap  which  screws  down  upon 
a  rubber  washer  and  closes  a  tube  communicating  with  the 
interior  of  the  box.  Upon  each  box  there  is  painted  by  the 
manufacturer  the  net  and  total  weights.  Shipping  regula- 
tions require  that  guncotton  should  be  wet  with  water  so  that 
the  water  is  20  per  cent  of  the  weight  of  guncotton  and  water. 
This  is  too  much  water  for  full  detonation,  and  the  gun- 
cotton  upon  receipt  at  a  post  should  be  dried  out  so  that  the 
weight  of  water  is  from  12  to  15  per  cent  of  that  of  the  dry 
guncotton.  The  guncotton  is  dried  by  opening  the  box  and 
pyramiding  the  guncotton  on  the  lid  and  in  the  box  so  that 
there  will  be  free  circulation  of  air  between  the  cakes.  The 
use  of  an  electric  fan  in  this  connection  will  ordinarily 
materially  facilitate  the  operation.  By  weighing  pilot  cakes 
it  may  be  determined  when  the  proper  amount  of  water  has 
evaporated.  The  guncotton  is  then  repacked,  lid  screwed 
down,  and  the  weight  chalked  upon  the  end  of  the  box.  The 
guncotton  should  be  placed  while  drying  so  that  it  is  not  in 
the  sunlight  and  should  be  handled  with  clean  cotton  or 
rubber  gloves. 

In  addition  to  the  regular  monthly  inspection  the  boxes 
are  reweighed  quarterly  under  the  supervision  of  the  officer 
responsible  for  submarine-mine  explosive,  and  the  gross 
weight  so  found  chalked  upon  the  end.  Should  any  box 
show  any  decided  decrease  in  weight  the  screw  cap  in  the  lid 
is  removed,  enough  fresh  water,  preferably  distilled  or  rain 
water,  added  to  bring  it  up  to  its  original  weight,  and  the 
screw  cap  replaced. 


SUBMARINE   MINING.  71 

Magazines  in  which  guncotton  is  stored  should  not  be 
allowed  to  attain  a  temperature  as  high  as  100°  F.  for  any 
length  of  time. 

Guncotton  which  is  kept  wet  may  deteriorate  after  long 
storage,  but  will  not  become  dangerous. 

Wet  guncotton  can  not  be  ignited  by  a  flame,  but  gradually 
smoulders  away  as  the  outer  portions  in  contact  with  the 
flame  become  dried. 

A  brownish  or  reddish  shade  is  sometimes  seen  in  cakes  of 
guncotton.  This  is  due  to  the  presence  of  iron  in  the  wash 
water  and  does  not  indicate  decomposition. 

When  storing  guncotton  in  the  magazine  the  piles  of  boxes 
should  be  made  so  as  to  give  free  circulation  of  air  and  the 
greatest  convenience  in  handling  consistent  with  the  capacity 
of  the  magazine. 

In  the  event  of  damage  to  any  case,  which  may  cause  loss 
of  water  by  evaporation,  the  contents  shall  be  removed  at 
once,  repacked  in  a  guncotton  box  which  has  been  washed 
with  soda  solution,  the  proper  amount  of  water  added  to 
the  contents,  and  the  box  closed.  The  gross  weight  shall 
be  marked  on  the  case.  In  repacking  avoid  as  much  as  pos- 
sible handling  the  cakes  with  the  bare  hands.  This  is  for  the 
protection  of  the  guncotton  from  oil  or  acid  of  any  kind. 
Clean  cotton  or  rubber  gloves  are  suitable  covering  for  the 
hands  when  engaged  on  this  work. 

If  for  any  reason  the  cases  are  subjected  to  dampness 
sufficient  to  cause  unusual  deterioration  of  the  cases,  they 
should  be  removed  from  the  magazine  and  dried,  out  of  the 
direct  rays  of  the  sun. 

Guncotton  containing  12  or  15  per  cent  of  moisture  may  be 
stored  with  explosive  D,  trotol,  and  dynamite,  but  never  with 
dry  guncotton. 

Empty  cases,  before  being  placed  in  storage,  must  be 
washed  thoroughly  to  remove  all  traces  of  guncotton. 

For  a  charge  of  wet  guncotton,  the  priming  charge  is  dry 
guncotton.  This  may  be  either  of  crumbled  guncotton  or 
cakes  made  to  fit  the  fuse  can.  The  compressed  primer  cakes 
are  supplied  wet  and  bored  with  holes  to  receive  the  fuses 
and  the  loading  wire. 


72  SUBMARINE   MINING. 

Should  the  supply  of  guncotton  primers  become  exhausted 
fresh  ones  may  be  prepared  as  follows:  Two  blocks  of  soft 
pine  are  used,  one  3  inches  square,  the  other  circular  and  2.9 
inches  in  diameter.  A  cake  of  wet  guncotton  is  clamped 
between  these  blocks.  Using  a  fine  joiners'  saw  and  the  cir- 
cular block  as  a  gauge,  a  cylinder  is  sawed  from  the  cake. 
The  cylinder  is  then  smoothed  down  with  a  rasp.  Four  of 
these  are  prepared  for  each  charge  and  in  each  one  of  them  a 
hole  about  T%  inch  in  diameter  is  bored.  While  boring  the 
hole  the  cake  must  be  tightly  clamped  between  two  pine 
blocks  to  prevent  it  from  splitting;  to  insure  that  all  the 
holes  will  be  in  alignment  it  is  advisable  that  the  upper 
wooden  block  be  provided  with  a  T9g-inch  hole  and  be  thick 
enough  to  enable  this  hole  to  serve  as  a  guide  for  the  bit. 
The  boring  is  done  with  the  ordinary  bit,  which  must  be 
sharp,  so  as  to  cut  clean.  It  is  not  safe  to  saw  or  bore  a  dry 
guncotton  cake. 

It  is  essential  that  the  guncotton  primer  be  thoroughly 
dry.  The  primers  may  be  dried  by  exposure  to  the  air  or  by 
means  of  drying  ovens  supplied  especially  for  the  purpose. 
To  air-dry  a  primer,  it  is  placed  on  edge  upon  a  shelf  of  wire 
gauze  or  netting  which  is  hung  up  indoors  where  there  is  a 
free  circulation  of  dry  warm  air.  Drying  should  continue 
until  weighings  on  two  successive  days  show  no  appreciable 
loss.  This  may  require  a  week  or  more. 

In  drying  with  an  oven  the  cakes  are  laid  on  edge  on  the 
shelves  and  the  temperature  of  the  oven  is  kept  at  about  100° 
F.;  it  should  not  exceed  104°  F.  The  heat  is  provided  by 
means  of  a  bank  of  lamps  placed  under  the  hood  and  the 
current  of  warm  air  regulated  by  the  size  of  the  lamp  bank 
and  the  openings  in  the  top  of  the  oven.  Under  no  circum- 
stances must  an  open  flame  be  used  as  a  source  of  heat.  The 
drying  in  this  case  also  is  continued  until  successive  weigh- 
ings of  samples  show  no  appreciable  loss. 

Whenever  it  is  necessary  to  dry  more  than  50  pounds  of 
guncotton  primers  for  immediate  use  the  guncotton  should 
be  placed  in  the  drying  oven  and  exposed  to  the  action  of 
an  electric  fan  placed  about  4  feet  in  front  of  the  open  door 
until  the  moisture  content  is  reduced  to  about  6  per  cent, 


SUBMARINE    MINING.  73 

when  the  drying  should  be  completed  by  the  use  of  the  bank 
of  lamps  as  described  in  the  preceding  paragraph. 

In  each  case,  to  test  the  dryness  of  the  primers,  take  a  cake 
and  split  it  in  four  or  five  pieces  and  detonate  each  sepa- 
rately with  a  fuse. 

It  has  been  determined  that  about  5  per  cent  of  water  is 
the  maximum  content  for  unconfmed  guncotton  capable  of 
detonation  by  a  Du  Pont  No.  30  fuse. 

Priming  charges  are  not  to  be  prepared  until  just  previous 
to  the  time  they  are  to  be  used  in  loading.  When  the  primers 
have  been  dried,  they  should  be  kept  in  well-sealed  jars  unless 
they  are  to  be  used  very  soon  after  drying,  in  which  case  they 
will  be  stored  in  assembled  fuse  cans;  when  thus  stored  the 
assembled  fuse  cans  should  be  kept  in  a  cool,  dry,  and  secure 
room  away  from  other  explosives.  If,  however,  the  primers 
are  to  be  stored  for  any  length  of  time,  two  strips  of  blue 
litmus  paper  are  inserted  between  the  cakes,  which  are  in- 
spected from  time  to  time.  If  the  litmus  paper  shows  de- 
cided redness,  it  should  be  removed  and  fresh  strips  inserted. 
If  these  strips  turn  red  in  a  few  hours,  the  primers  should  be 
thoroughly  wet  with  fresh  water.  In  general,  the  period  of 
storage  will  be  short  and  no  particular  examination  of  the 
dry  guncotton  will  be  required. 

Dry  guncotton  should  be  handled  as  little  as  possible,  to 
prevent  crumbling  and  scattering  of  guncotton  dust.  Finely 
divided  guncotton  is  difficult  to  remove  by  brushing  and  if 
allowed  to  collect  about  a  room  may  give  serious  trouble  by 
flashing  should  a  portion  become  ignited.  This  dust  may  be 
removed  with  a  damp  sponge  or  cloth. 

Dry  guncotton  which  is  not  used  as  contemplated  shall  be 
rewet  with  the  proper  amount  of  water  and  repacked. 

Samples  of  each  lot  of  guncotton  issued  to  the  service  are 
preserved  in  the  laboratory  of  the  Ordnance  Department  for 
chemical  test.  These  retained  samples  are  subjected  regu- 
larly to  technical  inspection  and  test  by  that  department  to 
determine  their  condition  as  to  stability.  This  will  insure 
the  detection  of  lots  that  are  deteriorating  and  their  removal 
from  the  posts  or  their  destruction  before  they  have  dete- 
riorated to  such  an  extent  that  they  become  dangerous. 


74  SUBMARINE   MINING. 

Dynamite. — Dynamite  cartridges  are  packed  ordinarily  in 
sawdust  in  wooden  boxes.  Each  cartridge  is  wrapped  in 
paraffin  paper.  The  cartridges  are  arranged  in  the  box  so 
that  when  they  are  transported  all  cartridges  will  lie  on 
their  sides  and  never  on  their  ends.  Usually  the  amount  of 
explosive  in  a  single  package  will  not  exceed  50  pounds. 

The  boxes  must  never  be  allowed  to  stand  so  that  the 
cartridges  wrill  be  vertical. 

Like  other  nitroglycerin,  dynamite  freezes  at  about  40°  F., 
and  in  its  frozen  condition  is,  under  ordinary  circumstances, 
less  liable  to  explosion  from  detonation  or  percussion  than 
when  thawed,  but  more  susceptible  to  explosion  by  simple 
ignition.  Should  any  of  the  nitroglycerin  be  exuded,  the 
dynamite  cartridges  are  much  more  sensitive  to  explosion 
by  a  blow. 

It  is  important  that  dynamite  cartridges  be  kept  dry.  If 
exposed  to  a  moist  atmosphere,  there  is  a  tendency  of  the 
water,  condensed  from  the  air  on  all  exposed  surfaces,  to 
displace  the  nitroglycerin. 

The  cases  should  be  raised  from  the  floor  on  skids  and  the 
floor  underneath  covered  with  clean  sawdust.  The  sawdust 
should  be  removed  from  time  to  time,  the  old  sawdust  being 
burned  in  the  open  air. 

Kubber  gloves  should  be  worn  in  handling  this  explosive, 
or  in  the  absence  of  rubber  gloves  cover  the  hands  with 
grease  and  wear  cotton  gloves.  This  is  for  the  protection 
of  the  skin  from  the  injurious  effect  of  nitroglycerin. 

Dynamite  may  be  stored  with  wet  guncotton,  explosive  D, 
and  trotol. 

Date  of  receipt  at  post  shall  be  marked  on  each  box. 

The  priming  charge  for  dynamite  is  a  pound  of  loose 
dynamite  contained  in  a  small  bag  which  fits  easily  into  the 
fuse  can.  In  filling  the  bag  rubber  gloves  must  be  worn. 
To  insert  the  fuses  the  bag  is  opened  and  the  fuses  embedded 
in  the  explosive,  the  choke  being  tied  around  the  fuse  wires. 

At  the  monthly  inspection  all  boxes  shall  be  examined  to 
see  if  they  are  dry.  If  not  dry,  all  shall  be  exposed  to  the 
dry  air  out  of  the  direct  rays  of  the  sun. 


SUBMARINE    MINING.  75 

The  principal  source  of  danger  from  dynamite  is  in  the 
exudation  of  the  nitroglycerin.  Exudation  is  indicated  by 
the  presence  of  small  white,  oily,  lustrous  globules  of  liquid, 
either  among  the  particles  of  dynamite  or  on  the  packages. 
If  such'  globules  are  discovered,  they  may  be  identified  posi- 
tively as  nitroglycerin  by  absorbing  a  drop  in  a  piece  of  un- 
glazed  paper,  which  should  be  placed  on  an  anvil  or  other 
piece  of  metal,  and  striking  it  a  sharp  blow  with  a  hammer. 
If  it  be  nitroglycerin,  an  explosion  will  occur.  Another  test 
is  to  set  fire  to  the  paper,  and  if  the  liquid  be  nitroglycerin 
it  will  burn  with  a  crackling  noise  and  a  greenish-yellow 
flame. 

If  exuded  nitroglycerin  has  stained  floors  or  other  ma- 
terial not  readily  destroyed,  the  nitroglycerin  may  be  de- 
composed and  rendered  harmless  by  washing  with  "  sulphur 
solution."  This  solution  may  be  made  by  boiling  50  pounds 
of  lime  in  a  barrel  of  water  and  adding  powdered  sulphur 
until  the  solution  will  take  up  no  more.  This  will  require 
about  20  pounds  of  sulphur.  The  resulting  bright  orange- 
colored  solution  should  be  filtered  and  only  the  filtrate  used. 
A  suitable  filter  for  this  purpose  is  a  piece  of  thin  cheese- 
cloth. Sodium  carbonate  may  be  used  in  the  place  of  lime. 

Dynamite  may  be  destroyed  by  burning  in  small  quantities 
at  a  time.  Slit  the  cartridge  with  a  knife,  spread  out  the 
contents  over  some  straw  or  shavings,  and  ignite  carefully. 
Do  not  attempt  to  burn  frozen  dynamite. 

Mine  fuses. — These  are  regular  commercial  electric  fuses, 
extra  quality,  and  each  contains  about  25  grains  of  mer- 
cury fulminate.  Fuses  are  supplied  in  pasteboard  boxes 
containing  50  each,  pasteboard  boxes  being  shipped  in  suitable 
wooden  boxes.  They  are  supplied  with  long  leads  which  are 
cut  to  proper  length  when  the  mines  are  loaded.  They  must 
not  ~be  stored  with  other  explosives. 

Loading  mines. — In  loading  mines  the  following  precau- 
tions are  observed: 

(a)  Funnels  are  used  to  cover  the  screw  threads. 

(b)  Trotol  is  poured  through  the  funnels. 

(c)  Cakes   of   guncotton  or   packages   of   dynamite    are 
passed  through  the  funnels  by  hand. 


76  SUBMAKINE   MINING. 

(d)  The  screw   threads   are  wiped   carefully  before  the 
compound  plug  is  inserted. 

(e)  Pieces  of  canvas  or  paulins  should  be  spread  upon  the 
floor  of  the  loading  room.     After  the  loading  has  been  com- 
pleted the  canvas  should  be  removed  and  thoroughly  cleaned. 
The  floor  of  the  loading  room  should  be  scrubbed  and  all 
refuse  destroyed. 

Unloading  mines. — Mines  charged  with  trotol  or  wet  gun- 
cotton  may  be  unloaded  without  danger;  the  compound 
plug  being  unscrewed,  the  cakes  of  wet  guncotton  are  re- 
moved by  hand,  repacked  in  the  original  boxes,  a  little  fresh 
water  added,  and  the  boxes  closed.  If  loaded  with  trotol, 
the  charge  is  poured  out  into  the  boxes,  which  are  then 
closed.  Trotol  should  be  inspected  carefully  when  removed 
from  the  case,  and  if  there  is  indication  that  any  of  it  has 
undergone  a  change  while  the  mine  was  loaded,  a  report 
should  be  made  to  the  War  Department. 

In  unloading  mines  charged  with  dynamite  too  many  pre- 
cautions can  not  be  taken.  The  mine  should  be  held  either 
in  an  opening  in  a  raft  or  behind  an  earthen  traverse  and 
the  compound  plug  removed  by  some  arrangement  which 
may  be  operated  from  a  safe  distance.  If  the  mine  has 
been  planted  for  some  time  the  recovered  dynamite  is  usu- 
ally destroyed.  Sometimes  the  interior  of  the  mine  case  may 
be  found  coated  with  an  extremely  thin  film  of  exuded  nitro- 
glycerin.  This  film  may  be  destroyed  by  filling  and  thor- 
oughly rinsing  the  case  with  "  sulphur  solution." 


APPENDIX  NO.  2. 

THE  HORNSBY-AKROYD  OIL  ENGINE  AND  GENERATOR. 

(See  also  Artillery  Notes,  No.  12.) 

The  engine. — This  is  a  horizontal,  single-acting,  single- 
cylinder  kerosene  engine,  having  a  flyball  governor  and  oper- 
ating on  a  four-stroke  cycle.  This  cycle  consists  in  turn  of 
the  explosion  on  the  first  outstroke,  the  expulsion  of  the  prod- 
ucts of  the  explosion  on  the  following  instroke,  the  intake 
into  the  cylinder  of  a  mixture  of  air  and  oil  vapor  on  the 
following  outstroke,  and  the  compression  of  this  explosive 
mixture  on  the  next  instroke.  This  cycle  therefore  requires 
two  complete  revolutions  of  the  crank  shaft  for  one  complete 
set  of  operations. 

One  one  side  of  the  cylinder  near  the  closed  end  is  a  valve 
box  containing  two  valves,  the  air-inlet  valve  and  the  exhaust 
valve.  The  air  inlet  and  the  exhaust  valves  are  actuated  by 
separate  levers,  each  lever  being  moved  by  a  cam  mounted  on 
a  horizontal  shaft,  driven  by  the  crank  shaft  through  worm 
gearing.  This  horizontal  shaft  makes  but  one  revolution 
while  the  crank  shaft  makes  two ;  thus  the  air  inlet  and  the 
exhaust  valves  are  each  opened  once  every  two  revolutions 
of  the  flywheel. 

At  the  back  of  the  cylinder,  in  prolongation  of  its  axis,  is  a 
cast-iron  box  called  the  vaporizer,  which  is  always  open  to 
the  cylinder.  Before  starting  the  engine  this  vaporizer  must 
be  heated  by  an  external  lamp,  so  that  it  will  vaporize  the  oil 
when  it  is  first  pumped  into  it.  After  the  engine  has  started 
running,  the  lamp  is  no  longer  required,  as  the  vaporizer  is 
kept  at  a  sufficient  heat  by  the  internal  explosions. 

A  small  oil  pump,  worked  by  the  air-valve  lever,  draws 
oil  from  the  oil  tank  under  the  engine  and  forces  it  into  the 

11003°— 12 7  77 


78  SUBMARINE   MINING. 

vaporizer  at  the  proper  time.  The  oil,  on  its  way  from  the 
pump  to  the  vaporizer,  passes  through  a  valve  box  attached 
to  the  vaporizer ;  this  valve  box  has  two  valves  in  it,  a  hori- 
zontal one,  kept  closed  by  a  spring  which  the  oil  forces  open 
as  it  goes  into  the  vaporizer;  the  other,  a  vertical  one,  also 
kept  closed  by  a  spring.  Should  the  engine  run  too  fast,  the 
governor  opens  this  latter  valve  and  allows  some  of  the  oil 
to  flow  back  to  the  oil  tank  through  the  waste  pipe.  This 
valve  can  also  be  opened  by  turning  the  little  regulating 
handle,  which  will  stop  the  supply  of  oil  to  the  vaporizer 
and  thus  stop  the  engine. 

INSTRUCTIONS  FOB  WORKING. 

Frosty  weather. — If  there  is  danger  of  freezing,  on  shutting 
down  drain  the  water  from  the  circulating  pipes  and  cylinder 
jacket,  and  valve  box  if  water- jacketed;  otherwise  they  may 
burst  or  crack. 

Caution, — Before  starting,  see  that  the  cocks  which  admit 
water  to  the  water  jacket  of  the  vaporizer  valve  box  are 
open ;  that  the  cock  on  the  main  water  pipe  from  the  bottom 
of  the  water  tank  is  open ;  that  the  water  in  the  tank  is  above 
the  upper  circulating  pipe ;  that  the  drain  cock  is  closed ;  and 
that  the  oil  tank  is  filled  with  kerosene.  Gasoline  must  not 
be  used  with  this  engine. 

Heating  the  vaporizer. — Open  the  relief  cock  on  top  of  the 
engine  cylinder.  Place  the  lamp  on  the  stand  under  the 
vaporizer ;  fill  the  lamp  with  oil  by  means  of  the  filling  pipe 
till  the  oil  is  1  inch  below  the  pipe ;  and  put  a  piece  of  wick 
into  the  cups  which  are  formed  around  the  pipes.  These 
wicks,  which  should  consist  of  a  piece  of  ordinary  asbestos 
packing,  will  last  for  several  weeks.  Place  the  lid  of  the 
vaporizer  cover  crosswise  on  the  cover  to  allow  the  escape 
of  heated  gas  and  air. 

A  little  alcohol  or  kerosene  should  be  poured  into  the  cup 
under  the  coil  and  lighted.  The  cups  may  be  filled  with 
kerosene  by  closing  the  air-escape  valve  and  working  the  air 
pump.  The  pressure  forces  oil  out  through  the  vapor  nozzle 
and  it  will  run  down  into  the  cups.  When  this  is  nearly 


SUBMARINE    MINING.  79 

burned  out  pump  up  the  reservoir  with  air  by  the  air  pump. 
Oil  will  issue  from  the  small  nozzle  and  give  a  clear  flame. 
When  it  is  desired  to  stop  the  lamp,  turn  the  thumbscrew  on 
the  reservoir  filling  nozzle  to  let  the  air  out.  Should  the 
nozzle  become  choked  it  should  be  cleaned  with  the  small 
needles  for  that  purpose. 

The  heating  of  the  vaporizer  is  one  of  the  most  important 
things  to  be  attended  to,  and  care  must  be  taken  that  it  is 
hot  enough  at  starting.  The  attendant  must  see  that  the 
lamp  is  burning  properly  and  that  a  good  clear  flame  is  given 
off  for  from  5  to  10  minutes,  according  to  the  size  of  the 
engine.  If,  however,  the  lamp  is  burning  badly,  it  may  take 
longer  to  become  heated  sufficiently.  It  is  important  that 
this  should  be  carefully  attended  to,  for  though  the  engine 
may  start,  if  the  vaporizer  is  not  as  hot  as  it  should  be  the 
engine  will  run  badly  and  perhaps  soon  stop  altogether. 
Failures  of  engines  to  run  properly  can  in  most  cases  be 
traced  to  this  source. 

No  time  should  be  lost  in  starting  the  engine  after  the 
vaporizer  has  been  sufficiently  heated,  as  the  engine  may  not 
run  satisfactorily  if  the  vaporizer  is  allowed  to  cool  after 
heating  it.  The  lamp  should  be  left  burning  a  few  minutes 
after  starting. 

Oiling  the  engine. — Oiling  the  engine  should  always  be  done 
during  the  heating-up  of  the  vaporizer. 

See  that  the  oil  cups  on  the  two  main  crank-shaft  bearings 
are  fitted  with  proper  wicks  and  filled  with  oil.  Adjust  the 
lubricator  on  the  large  end  of  the  connecting-rod  and  oil  the 
small  end  which  is  inside  the  piston. 

Oil  also  the  following:  The  bearings  on  the  horizontal 
shaft  and  the  skew  gearing,  the  rollers  at  the  ends  of  the 
valve  levers  and  their  pins,  the  pins  on  which  the  levers  rock, 
the  governor  spindles  and  joints  and  the  bevel  wheels  which 
drive  the  same,  and  the  joints  that  connect  the  governor  to 
the  vertical  valve  of  the  overflow.  For  such  bearings  none 
but  the  best  engine  oil  should  be  used. 

It  is  necessary  that  a  suitable  oil  should  be  used  for  lubri- 
cating the  cylinder,  and  unless  such  an  oil  be  used  for  this 


80  SUBMARINE    MINING. 

purpose  the  engine  may  run  badly  and  perhaps  stop  alto- 
gether. Under  no  circumstances  must  a  thick  cylinder  oil 
be  used,  and  the  oil  must  not  be  used  over  again  on  the  piston. 
Do  not  use  ordinary  lubricating  oil.  A  high-grade  gas- 
engine  oil  especially  suited  to  this  engine  should  be  used  and 
the  piston  should  be  kept  flooded  with  it. 

Starting  the  engine. — Throw  the  hand  lever  to  u  To  start." 
Turn  the  small  crutch-handle  regulator  Y  to  the  position 
"  Shut "  and  work  the  pump  lever  up  and  down  until  oil  is 
seen  to  pass  the  overflow  freely.  Turn  the  regulator  back  to 
"  Open,"  work  the  pump  lever  up  and  down  a  few  strokes. 
Vapor  should  issue  with  some  force  from  the  relief  cock  on 
the  cylinder.  This  indicates  sufficient  heat.  Close  the  relief 
cock  and  pump  a  few  strokes.  Man  the  flywheel  and  start 
the  flywheel  backward,  using  the  weight  of  the  body  if  neces- 
sary, bringing  the  piston  up  against  compression  as  sharply 
as  possible,  and  then  release  the  wheel,  when  an  explosion 
should  take  place  and  the  engine  start  forward.  As  soon  as 
the  engine  has  sufficient  speed  to  carry  it  past  a  full  compres- 
sion, throw  the  lever  to  "To  work."  When  full  speed  is 
obtained,  cut  down  the  pump  stroke  to  correspond  to  the 
load,  open  the  oil  feeders,  and  go  over  the  engine  carefully, 
seeing  that  the  cylinder  oil  feed  is  working. 

Oil  pump. — When  the  cylinder  is  working  at  its  full  power 
the  distance  between  the  round  flanges  on  the  pump  plunger 
should  be  such  that  the  hand  gauge  (supplied  with  the  en- 
gine, and  to  be  found  in  the  tool  box)  will  allow  the  part 
stamped  "  1 "  just  to  fit  in  between  the  flanges ;  if  at  any  time 
the  positions  of  these  flanges  be  altered  they  can  be  read- 
justed to  this  gauge.  The  other  lengths  on  the  hand  gauge 
are  useful  for  adjusting  the  pump  to  economize  oil.  When 
running  on  a  medium  load,  use  length  marked  2 ;  on  a  light 
load,  use  length  marked  3.  See  that  the  pump  packing  is 
not  too  tight. 

Running  the  engine  light. — When  the  engine  is  to  run 
light — that  is,  with  no  load  or  with  a  light  load — it  is  best 
to  alter  the  stroke  of  the  pump  to  the  amount  of  oil  that  will 
keep  the  engine  running.  This  amount  can  be  reduced  so 
that  the  speed  of  the  engine  is  a  few  revolutions  under  the 


SUBMARINE    MINING.  81 

normal,  which  will  allow  the  vaporizer  to  get  a  small  charge 
each  time  and  keep  it  from  cooling.  The  cock  on  the  return 
of  the  water  circulating  pipe  may  be  nearly  closed  to  keep 
the  cylinder  warmer.  These  remarks  do  not  apply  when  the 
load  is  intermittent  and  the  engine  is  running  light  for  a 
short  time  only. 

Air-inlet  and  exhaust  valves. — See  that  the  air-inlet  and 
the  exhaust  valves  are  always  working  properly  and  drop 
onto  their  seats.  They  can  at  any  time,  if  required,  be  made 
tight  by  grinding  with  a  little  flour  of  emery  and  oil. 

To  insure  a  good  seat  to  the  valves  when  the  stems  are 
expanded  by  heat  the  stems  should  clear  the  set  screws  on 
the  levers  at  least  -fa  inch  when  the  air  and  the  exhaust  levers 
are  clear  of  the  cams.  A  greater  clearance  is  undesirable,  as 
it  prevents  the  full  opening  of  the  valves. 

If  at  any  time  the  air-inlet  or  the  exhaust  valves  appear  to 
be  opening  or  closing  at  the  wrong  time,  take  off  the  nut  on  the 
end  of  the  lay  shaft  which  holds  the  skew  wheel  on  and  see 
that  the  chisel  cuts  on  the  shaft  are  opposite  to  one  another. 
The  lay  shaft  is  coned  where  the  skew  wheel  is  fixed  on  and 
it  is  held  on  simply  by  friction,  the  nut  being  tightened 
against  it.  -i 

Should  it  at  any  time  become  necessary  to  take  out  the 
crank  shaft,  always  be  sure  that  the  skew-wheel  gearing  is 
put  together  so  that  the  tooth  marked  "  0  "  on  the  crank-shaft 
skew- wheel  fits  in  between  the  two  teeth  marked  "  0  "  on  the 
oil-shaft  skew-wheel. 

Vaporizer  valve  box  and  pipes  attached  to  vaporizer. — In  this 
box  there  are  two  valves.  The  vertical  one  is  regulated  by 
the  governor,  and  when  the  engine  runs  faster  than  its 
proper  speed  the  governor  pushes  it  down,  thus  opening  it 
and  allowing  some  oil  to  return  to  the  oil  tank.  The  hori- 
zontal valve  in  this  box  is  a  back-pressure  valve.  If  at  any 
time  this  valve  is  not  working  properly,  vapor  will  be  seen 
coming  out  of  the  overflow  pipe ;  in  this  case  the  valve  should 
be  examined.  By  screwing  off  the  outside  cap  the  tail  of 
this  valve  can  be  seen;  if  the  valve  is  turned  around  a  few 


82  SUBMARINE   MINING. 

times  it  will  probably  dislodge  any  dirt  that  may  be  under 
it;  if,  however,  this  does  not  stop  the  leakage  the  valve 
should  be  taken  out  for  inspection. 

If  the  horizontal  valve  and  sleeves  are  taken  out  at  any 
time,  great  care  must  be  taken  in  replacing  them  to  use  the 
same  thickness  of  jointing  material  as  before  or  the  distance 
the  valve  opens  will  be  altered. 

See  that  the  pipe  from  the  pump  to  the  vaporizer  valve 
box  is  inclined  upward  all  the  way  from  the  pump.  If  this 
is  not  so,  an  air  pocket  will  be  formed  in  which  a  certain 
amount  of  air  will  be  compressed  upon  each  stroke  of  the 
pump.  This  will  cause  the  oil  to  flow  in  slowly  and  not 
suddenly  as  it  should.  If  the  oil  tank  be  emptied  of  oil  at 
any  time,  air  will  get  into  the  suction  and  delivery  pipes  of 
the  pump  and  it  will  take  some  time  before  the  oil  going 
through  the  pump  and  pipes  will  be  free  of  this  air;  for 
awhile  thereafter,  the  engine  will  not  work  properly,  as  the 
air,  by  being  compressed  as  the  pump  works,  will  interfere 
with  oil  being  pumped  in  suddenly.  It  is  best,  if  the  oil 
gets  below  the  filter  in  the  tank,  to  work  the  pump  by  hand 
for  about  10  minutes,  holding  the  relief  valve  (on  the  vapor- 
izer box)  so  as  to  get  air  well  out  of  the  pipes. 

To  stop  the  engine. — Turn  the  crutch-handle  regulator  to 
"  Shut."  Close  the  automatic  lubricator.  If  it  is  desired  to 
stop  the  engine  for  a  short  time  only,  put  the  lamp  back 
under  the  vaporizer  to  keep  it  hot. 

Setting  the  oil  engine  and  the  generator. — The  engine  and 
generator  should  be  so  located  that  the  distance  from  center 
to  center  of  pulleys  should  be  as  nearly  correct  as  possible 
when  the  generator  is  at  the  middle  point  of  the  base  rails,  so 
that  the  proper  tension  of  the  belt  may  be  obtained  within 
the  limits  of  adjustment  allowed  by  the  rails. 

The  two  pulleys  should  be  accurately  in  line  and  the  belt 
not  too  tight.  The  generator  base  should  rest  on  a  wooden 
frame  to  separate  it  from  the  concrete  pier.  Both  engine 
and  generator  should  be  held  firmly  in  position  by  anchor 
bolts. 

For  the  generator  bearings  a  quantity  of  the  best  dynamo 
oil  is  furnished ;  the  commutator  should  be  clean  and  smooth, 


SUBMARINE   MINING.  83 

and  the  brushes  should  fit  the  surface.  The  commutator 
should  be  cleaned  occasionally  with  a  little  paraffin  on  can- 
vas, and  the  brushes  should  be  adjusted,  so  that  when  running 
at  full  load  no  sparking  occurs. 

All  electrical  connections  should  be  firmly  made  and  kept 
thoroughly  clean.  A  cover  should  be  kept  on  the  generator 
when  not  in  use.  If  the  machine  be  damp  it  should  be 
allowed  to  dry  before  running  at  full  load. 

NOTE. — A  few  new  installations  have  been  supplied  with  5-kw.  gaso- 
line electric  sets,  and  future  installations  will  be  similarly  equipped. 
Wherever  installed,  pamphlets  on  the  care  and  operation  of  the  gaso- 
line sets  have  been  furnished,  containing  full  instructions  for  the 
guidance  of  those  concerned. 


APPENDIX  NO.  3. 
THE  STORAGE  BATTERY. 

(See  pamphlets  issued  by  the  Electric  Storage  Battery  Co.,  Philadel- 
phia, Pa.,  on  General  Instructions  for  the  Operation  and  Care  of 
the  Chloride  Accumulator.) 

Unpacking  material. — Great  care  should  be  taken  in  the  un- 
packing and  subsequent  handling  of  the  various  parts  of  the 
battery,  as  many  of  them  are  easily  broken  or  bent  out  of 
shape  by  rough  handling. 

Open  the  crates  or  packing  boxes  on  the  side  marked  "  Up  " 
and  carefully  lift  contents  out ;  never  slide  them  out  by  turn- 
ing the  crate  on  its  side. 

Upon  opening  the  crates  and  boxes,  carefully  count  the  con- 
tents of  each  package,  and  check  with  the  shipping  list.  A 
number  of  small  parts  will  usually  be  found  in  each  shipment, 
and  care  should  be  taken  to  examine  the  packing  materials 
to  determine  that  no  parts  have  been  overlooked. 

Immediately  upon  opening  the  crates  the  materials  should 
be  carefully  examined  for  breakage.  Cracked  jars,  whether 
of  glass  or  rubber,  should  not  be  set  up,  for  if  put  into  use 
leakage  of  electrolyte  may  cause  annoyance  or  trouble. 

Location  of  battery  room. — The  proper  location  of  the  bat- 
tery is  important.  It  should  be  in  a  separate  room,  which 
should  be  well  ventilated,  dry,  and  of  moderate  temperature. 
Extremes  of  temperature  affect  the  proper  working  of  a  bat- 
tery. The  air  should  be  dry,  for  if  damp  there  is  danger  of 
leakage  due  to  grounds. 

The  ventilation  should  be  free,  not  only  to  insure  dryness, 
but  to  prevent  chance  of  an  explosion,  as  the  gases  given  off 
during  charge  form  an  explosive  mixture  if  confined.  For 
this  reason  never  bring  an  exposed  flame  near  the  battery 
when  it  is  gassing. 
84 


SUBMARINE   MINING.  85 

Direct  sunlight  should  not  fall  on  the  cells. 

The  trays,  the  benches  on  which  the  cells  ^est,  and  all 
metal  work  (iron  and  copper)  should  be  painted  with  as- 
phaltum  varnish. 

Assembling  and  placing  cells  in  position. — Place  the  jars, 
after  they  have  been  cleaned,  in  position  on  the  stands,  which 
should  be  provided  for  the  purpose  and  which  should  be  so 
situated  in  the  room  that  each  cell  will  be  easily  accessible. 
The  jars  are  set  in  the  trays,  which  previously  should  be 
filled  with  fine  dry  sand  even  with  the  top,  the  trays  resting 
on  the  glass  insulators. 

Place  the  elements  as  they  come  from  the  packing  cases  on 
a  convenient  stand  or  table  (the  elements  are  packed  positive 
and  negative  plates  together;  the  positive  has  plates  of  a 
brownish  color,  the  negative  of  a  light  gray — the  negative 
always  has  one  more  plate  than  the  positive),  cut  the  strings 
that  bind  them  together,  and  carefully  pull  the  positive  and 
negative  groups  apart,  throwing  the  packing  aside.  After 
carefully  looking  over  both  groups  and  removing  any  dirt  or 
other  foreign  matter,  assemble  them,  with  separators  between 
each  positive  and  negative  plate. 

When  putting  into  the  jars  be  careful  that  the  direction  of 
the  lugs  is  relatively  the  same  in  each  case,  thus  causing  a 
positive  lug  of  one  cell  always  to  connect  with  a  .negative  of 
the  adjoining  one,  and  vice  versa.  This  insures  the  proper 
polarity  throughout  the  battery,  bringing  a  positive  lug  at 
one  free  end  and  a  negative  at  the  other. 

Before  bolting  or  clamping  the  lugs  together,  they  should 
be  well  scraped  at  the  point  of  contact  to  insure  good  conduc- 
tivity and  low  resistance  of  the  circuit;  this  should  be  done 
before  the  elements  are  taken  apart  and  directly  after  un- 
packing, if  the  battery  is  to  be  set  up  at  once.  The  connec- 
tions should  be  gone  over  and  tightened  several  times  after 
the  lugs  are  first  fastened  together  to  insure  good  contact. 

Connecting  up  the  charging  circuit. — Before  putting  the 
electrolyte  into  the  cells,  the  circuits  connecting  the  battery 
with  the  charging  source  must  be  complete,  care  being  taken 
to  have  the  positive  pole  of  the  charging  source  connected 
with  the  positive  end  of  the  battery. 


86  SUBMARINE   MINING. 

Electrolyte.— The  electrolyte  is  dilute  sulphuric  acid  of  a 
specific  gravity  of  1.210  or  25°  Baume,  as  shown  on  the 
hydrometer  at  temperature  of  70°  F. 

The  electrolyte  should  cover  the  top  of  the  plates  by  one- 
half  inch  to  three- fourths  inch,  and  must  be  cool  when 
poured  into  the  cells.  The  jars  should  be  numbered  with 
asphaltum  varnish  and  a  line  made  with  the  same  material 
to  indicate  the  height  at  which  the  electrolyte  should  be  kept. 

Initial  charge. — The  charge  should  be  started  at  the  normal 
rate  as  soon  as  the  electrolyte  is  in  the  cells  and  continued 
at  the  same  rate,  provided  the  temperature  of  the  electrolyte 
is  well  below  100°  F.,  until  there  is  no  further  rise  or 
increase  in  either  the  voltage  or  specific  gravity  over  a 
period  of  10  hours,  and  gas  is  being  given  off  freely  from 
all  the  plates.  Also,  the  color  of  the  positive  plates  should 
be  a  dark  brown  or  chocolate  and  that  of  the  negatives  a  light 
neutral  gray.  The  temperature  of  the  electrolyte  should  be 
closely  watched  and,  if  it  approaches  100°  F.,  the  charging 
rate  must  be  reduced  or  the  charge  stopped  entirely  until  the 
temperature  stops  rising.  From  45  to  55  hours  at  the  normal 
rate  will  be  required  to  complete  the  charge ;  but  if  the  rate  is 
less,  the  time  will  be  proportionately  increased.  The  specific 
gravity  will  fall  rapidly  after  the  electrolyte  is  added  to  the 
cells,  and  may  continue  to  fall  for  some  time  after  charging 
begins.  It  will  finally  rise  as  the  charge  progresses,  until  it 
is  again  up  to  1.210  or  possibly  slightly  higher.  The  voltage 
for  each  cell  at  the  end  of  charge  will  be  between  2.5  and  2.7 
volts,  and  for  this  reason  a  fixed  or  definite  volage  should 
not  be  aimed  for.  It  is  of  the  utmost  importance  that  this 
charge  be  complete  in  every  respect. 

At  the  end  of  the  first  charge  it  is  well  to  discharge  the 
battery  about  one-half  and  then  immediately  recharge  it. 
Repeat  this  treatment  two  or  three  times  and  the  battery 
will  be  in  proper  working  condition. 

After  the  completion  of  a  charge  (initial  or  with  the  bat- 
tery in  regular  service)  and  the  current  off,  tjie  voltage  will 
fall  immediately  to  about  2.20  volts  per  cell,  and  then  to  2 
volts  when  the  discharge  is  started.  If  the  discharge  is  not 
begun  at  once,  then  the  pressure  will  fall  quite  rapidly  to 


SUBMARINE   MINING.  87 

about  2.05  volts  per  cell,  and  there  remain  while  the  battery 
is  on  open  circuit. 

Battery  in  regular  service. — A  battery  must  not  be  repeat- 
edly overcharged,  undercharged,  overdischarged  or  allowed 
to  stand  completely  discharged.  After  the  initial  charge  is 
completed,  the  battery  is  ready  to  be  put  into  regular  service. 

A  cell  should  be  selected  as  a  "  pilot  cell " ;  that  is,  one 
that  is  in  good  condition  and  representative  of  the  general 
condition  of  the  battery.  The  height  of  the  electrolyte  in 
this  cell  must  be  kept  constant  by  adding  a  small  quantity  of 
water  each  day.  This  cell  is  to  be  used  particularly  in  fol- 
lowing the  charge  and  indicating  when  it  should  be  stopped. 

When  the  battery  is  in  regular  service,  the  discharge  should 
not  be  carried  below  1.75  volts  per  cell  at  full  load.  Stand- 
ing completely  discharged  will  cause  permanent  injury; 
therefore  the  battery  should  be  immediately  recharged  after 
a  heavy  discharge. 

In  usual  service,  with  the  normal  rate,  it  is  advisable  to 
stop  the  discharge  at  1.90  volts  per  cell.  If  the  discharge 
rate  is  considerably  less  than  normal,  the  voltage  should  not 
be  allowed  to  fall  as  low  as  1.90  volts  per  cell,  for  the  reason 
that  with  a  very  low  rate  of  discharge  the  voltage  will  not 
begin  to  fall  off  until  the  limit  of  capacity  is  almost  reached. 
The  fall  in  specific  gravity  of  the  electrolyte  also  serves  as 
an  indication  of  the  amount  taken  out  and  is  in  direct  pro- 
portion to  the  ampere-hour  discharge,  thereby  differing  from 
the  drop  in  voltage,  which  varies  irregularly  for  different 
rates  and  degrees  of  discharge.  For  this  reason,  under  ordi- 
nary conditions,  the  fall  in  specific  gravity  is  to  be  preferred 
in  determining  the  amount  of  discharge. 

The  actual  amount  of  variation  in  the  specific  gravity  of 
the  electrolyte  between  a  condition  of  full  charge  and  a  com- 
plete discharge  is  dependent  upon  the  quantity  of  solution  in 
the  containing  vessel  compared  with  the  bulk  of  the  plates. 
When  cells  are  equipped  with  the  full  number  of  plates,  the 
range  will  be  about  35  points  (0.035  sp.  gr.)  ;  for  instance, 
if  the  maximum  specific  gravity  reached  on  the  preceding 
overcharge  is  1.209,  the  extreme  limit  beyond  which  the  dis- 
charge should  not  be  carried  is  about  1.174.  If  the  cells  have 


88  SUBMARINE   MINING. 

less  than  the  full  number  of  plates,  this  range  in  specific 
gravity  is  proportionately  reduced,  except  in  the  case  of  the 
"pilot  cell,"  which  should  be  equipped  with  a  device  for 
displacing  the  excess  electrolyte. 

The  available  capacity  is  temporarily  reduced  at  low  tem- 
peratures ;  with  a  return  to  normal  temperature  the  capacity 
is  regained. 

The  battery  should  preferably  be  charged  at  the  normal 
rate.  It  is  important  that  it  should  be  sufficiently  charged, 
but  the  charge  should  not  be  repeatedly  continued  beyond 
that  point.  Both  from  the  standpoint  of  efficiency  and  life 
of  the  plates  the  best  practice  is  the  method  which  embraces 
what  may  be  called  a  regular  charge,  to  be  given  when  the 
battery  is  from  one-half  to  two-thirds  discharged,  and  an 
overcharge  to  be  given  weekly  if  it  is  necessary  to  charge 
daily,  or  once  every  two  weeks  if  the  regular  charge  is  not 
given  so  often. 

The  regular  charge  should  be  continued  until  the  specific 
gravity  of  the  pilot  cells  has  risen  to  within  five  points  of  the 
maximum,  as  shown  on  the  last  previous  overcharge.  For  ex- 
ample, if  on  the  previous  overcharge  the  maximum  is  1.210, 
then  on  the  following  regular  charges  the  current  should  be 
cut  off  when  the  specific  gravity  of  the  pilot  cell  reaches  1.205. 
The  pilot-cell  method  of  noting  the  end  of  charge  should  not 
be  used  with  a  battery  unless  all  the  cells  are  approximately 
in  the  same  condition.  With  an  old  battery  whose  plates  are 
not  uniform,  readings  should  be  taken  on  each  cell  to  deter- 
mine the  end  of  charge. 

The  overcharge  should  be  prolonged  until  all  the  cells  gas 
freely  and  until  no  rise  in  the  specific  gravity  and  voltage  of 
the  pilot  cell  is  shown  for  five  successive  15-minute  readings. 

Just  before  the  overcharge  the  cells  should  be  carefully 
examined  to  see  that  they  are  free  from  short  circuits.  If  any 
short  circuits  are  found  they  should  be  removed  with  a  stick 
or  a  piece  of  hard  rubber ;  do  not  use  metal. 

AJS  the  temperature  affects  the  specific  gravity  this  must  be 
considered  and  correction  made  for  any  change  of  tempera- 
ture. The  temperature  correction  is  one  point  (0.001  sp.  g.) 
for  3  degrees  change  in  temperature.  For  instance,  electro- 


SUBMAKINE    MINING.  89 

lyte,  which  is  1.210  at  70°,  will  be  1.213  at  61°  and  1.207 
at  79°. 

Inspection. — In  order  that  the  battery  may  continue  in  the 
best  condition  it  is  essential  that  specific  gravity  and  voltage 
readings  be  taken  on  all  cells  in  the  battery  at  least  once  a 
week;  the  specific  gravity  readings  on  the  day  before  the 
overcharge  and  the  voltage  reading  near  the  end ;  the  voltage 
readings  must  always  be  taken  when  the  current  is  flowing, 
open  circuit  readings  being  of  no  value.  Also,  at  the  end  of 
each  charge  it  should  be  noted  that  all  of  the  cells  are  gassing 
moderately  and  at  the  end  of  the  overcharge  very  freely. 

Unevenness  of  cells;  cause  and  remedy. — If  any  of  the  cells 
should  read  low  at  either  time  and  do  not  gas  freely  with 
the  others  at  the  end  of  charge,  examine  them  carefully  for 
pieces  of  scale  or  foreign  matter  which  may  have  lodged  be- 
tween the  plates.  If  any  are  noted,  remove  them  by  pushing 
down  into  the  bottom  of  the  jar  with  a  strip  of  wood.  Never 
use  metal  of  any  kind  for  this  purpose. 

If,  after  the  cause  of  the  trouble  has  been  removed,  the 
readings  do  not  come  up  at  the  end  of  the  overcharge,  then 
the  cell  must  be  cut  out  of  circuit  on  the  discharge,  to  be  cut 
in  again  just  before  beginning  the  next  charge,  during  which 
it  should  come  up  all  right. 

Impurities  in  the  electrolyte  will  cause  a  cell  to  work 
irregularly  and  the  plates  to  deteriorate.  Should  it  be 
known  that  any  impurity  has  gotten  into  the  electrolyte, 
steps  should  be  taken  to  remove  it  at  once.  The  solution 
should  be  replaced  with  new  immediately,  thoroughly  flush- 
ing the  cell  with  water  before  putting  in  the  new  electrolyte. 
The  change  should  be  made  when  the  battery  is  discharged, 
for  the  impurities  will  be  in  the  electrolyte  when  the  battery 
is  discharged.  Immediately  after  the  change  the  cell  should 
be  charged.  If  in  doubt  as  to  whether  the  electrolyte  con- 
tains impurities,  a  half -pint  sample,  taken  at  the  end  of  dis- 
charge, should  be  submitted  for  test. 

Sediment. — The  accumulation  of  sediment  in  the  bottom  of 
the  jars  must  be  watched  and  not  allowed  under  any  circum- 
stances to  get  up  to  the  plates ;  if  this  occurs,  rapid  deteriora- 
tion will  result.  To  remove  the  sediment,  the  simplest  way, 


90  SUBMARINE   MINING. 

if  the  cells  are  small,  is  to  lift  the  elements  out  after  the 
battery  has  been  fully  charged,  draw  off  the  electrotyte,  and 
then  dump  the  sediment,  and  clean  the  jar  with  water,  get- 
ting the  elementvS  back  and  covered  with  electrolyte  again  as 
quickly  as  possible,  so  that  there  will  be  no  chance  of  the 
plates  drying  out.  Electrolyte,  not  water,  will  be  required 
to  complete  the  filling  of  the  cells,  the  specific  gravity  being 
adjusted  to  standard  (1.210  at  the  end  of  charge). 

Evaporation. — Do  not  allow  the  surface  of  the  electrolyte  to 
get  down  to  the  top  of  the  plates;  keep  it  at  its  proper  level 
(one-half  inch  to  three- fourths  inch  above  the  top  of  the 
plates)  by  the  addition  of  pure  water;  which  should  be 
added  at  the  beginning  of  a  charge,  preferably  the  over- 
charge. It  will  not  be  necessary  to  add  electrolyte  except 
at  long  intervals  or  when  cleaning,  as  noted  above.  Elec- 
trolyte added  to  replace  loss  should  be  of  specific  gravity 
1.210. 

Battery  used  but  occasionally. — If  the  battery  is  to  be  used 
at  infrequent  periods,  it  should  be  given  a  "  freshening " 
charge  every  two  weeks. 

Putting  the  battery  out  of  commission. — If  it  is  thought  best 
to  put  the  battery  out  of  commission  for  a  time,  then  it  must 
be  treated  as  follows :  After  thoroughly  charging,  syphon  off 
the  electrolyte  (which  may  be  used  again)  into  convenient 
receptacles,  preferably  carboys  which  have  been  previously 
cleaned  and  have  never  been  used  for  other  kinds  of  acid, 
and  as  each  cell  becomes  empty  immediately  fill  it  with  fresh, 
pure  water.  When  water  is  in  all  the  cells  allow  them  to 
stand  12  to  15  hours,  then  draw  off  the  water;  the  battery 
may  then  stand  without  further  attention  until  it  is  again 
to  be  put  into  service;  then  proceed  as  in  the  case  of  the 
initial  charge,  as  described  above. 

If  for  any  reason  any  cell  becomes  discharged  before  the 
others,  it  should  be  cut  out  on  discharge  and  worked  up  to 
normal  before  being  used. 

Should  the  battery  sulphate,  charge  and  discharge  fre- 
quently, not  using  less  than  one-half  normal  rate  at  any  time 
and  increasing  to  full  rate  as  the  plates  show  signs  of 


SUBMAKINE    MINING.  91 

recuperation ;  keep  the  temperature  of  the  cells  below  100°  F. 
Frequent  exercise  will  clear  the  plates  in  a  badly  sulphated 
battery. 

Keep  careful  records  of  all  charging  voltages,  specific 
gravities,  and  troubles  with  the  cells. 

The  following  is  a  recapitulation  of  the  important  points 
in  operating  a  storage  battery: 

CONDENSED  INSTRUCTIONS. 

1.  Excessive  charging  must  be  avoided.     A  battery  should 
not  be  undercharged,  overdischarged,  or  allowed  to  stand 
completely  discharged. 

2.  Keep  the  electrolyte  at  the  proper  height  above  the  top 
of  the  plates. 

3.  The  daily  and  weekly  readings  should  be  regularly  and 
accurately  taken  and  recorded. 

4.  Inspect  each  cell  of  the  battery  carefully  at  regular 
intervals. 

5.  If  any  low  cells  develop  do  not  delay  in  bringing  them 
back  to  condition. 

6.  Do  not  allow  the  sediment  to  get  up  to  the  plates. 

7.  Do  not  allow  impurities,  either  solid  or  liquid,  to  get 
into  or  remain  in  the  cells. 

8.  Have  the  battery  room  well  ventilated,  especially  while 
charging. 

9.  Never  bring  an  exposed  flame  into  the  battery  room 
during  or  shortly  after  the  gassing  period  of  a  charge. 

10.  Keep  the  floor  and  other  parts  of  the  battery  room 
clean  and  dry. 

11.  Keep  the  iron,  copper,  or  other  metal  work  about  the 
battery  room  free  from  corrosion. 

12.  Keep  all  connections  clean  and  tight. 

13.  Post  a  copy  of  these  condensed  instructions  in  a  con- 
spicuous place. 


APPENDIX  NO.  4. 
SUBMARINE  MINE  CABLE. 

Submarine  mine  cable  is  shipped  on  reels  having  an  outer 
sheathing  for  protection  in  transit,  with  at  least  12  feet  of 
both  ends  of  the  cable  brought  out  and  coiled  on  the  head  of 
the  reel  for  test  purposes.  If  the  cable  is  not  for  imme- 
diate use,  it  should  be  moved  to  the  cable  tank,  and  by  means 
of  the  overhead  trolley  and  cable  tongs  put  in  its  position  in 
the  tank,  the  two  ends  being  properly  tagged  and  firmly  fixed 
so  as  to  allow  it  to  be  tested.  In  arranging  the  multiple 
cable  in  the  tanks  that  which  is  to  be  used  first  should  be 
most  readily  accessible. 

The  cable  tank  should  be  provided  with  a  cover  to  keep  it 
clean,  as  well  as  to  lessen  as  much  as  possible  variations  of 
temperature.  Enough  clean  water  to  cover  by  several  inches 
the  outer  sheathing  of  the  cable  reels  should  be  kept  in  the 
tanks,  but  in  climates  where  the  water  in  the  cable  tanks 
would  normally  freeze  to  a  depth  exceeding  2  feet,  the  water 
should  be  let  out  of  the  tanks  before  ice  begins  to  form  and 
not  again  admitted  until  the  following  spring.  In  localities 
where  the  tanks  may  become  a  breeding  place  for  mosquitoes, 
as  a  preventive  measure,  salt  water  from  the  ocean  or  bay 
should,  when  practicable,  be  used  for  filling  the  tanks,  or 
where  it  is  necessary  to  use  fresh  water  sufficient  salt  should 
be  added  to  produce  a  3  per  cent  solution.  No  oil  or  kerosene 
should  be  used  in  the  tanks. 

The  methods  of  recording  tests  and  of  classifying  and 
transferring  submarine  mine  cable  are  prescribed  by  orders 
from  the  War  Department.  The  tests  of  submarine  mine 
cable  at  posts  will  consist  in  determining  the  insulation  and 
conductor  resistances. 

The  insulation  surrounding  the  conductor  of  a  cable  is 
supposed  to  be  uniform  in  regard  to  quality  of  material, 
92 


SUBMARINE    MINING.  93 

density,  and  thickness.  The  resistance  which  it  offers  to 
the  passage  of  a  current  through  it  will  then  vary  inversely 
with  its  length.  In  comparison  the  insulation  resistance  of 
1  mile  of  cable  is  taken  as  the  standard.  This  insulation  has 
a  large  negative  temperature  coefficient;  that  is,  an  increase 
of  temperature  lowers  its  resistance.  It  is  customary  to 
reduce  all  insulation  resistance  to  that  at  a  standard  tempera- 
ture of  60°  F.,  and  for  this  purpose  reduction  factors  ap- 
plicable to  the  particular  insulation  compound  should  be 
furnished  with  the  cable.  (Note :  It  has  been  found  that  for 
most  compounds,  if  the  logarithms  of  the  resistance  are  plot- 
ted as  ordinates  against  the  temperature  in  degrees  F.  as 
abscissae,  the  resulting  curve  will  be  very  nearly  a  straight 
line. ) 

The  ordinary  methods  of  measuring  resistance — that  is,  by 
means  of  a  Wheatstone  bridge,  or  by  fall  of  potential,  or  by 
voltmeter — can  not  be  used  in  measuring  resistance  as  high 
as  that  of  the  insulation  of  a  submarine  cable.  For  this  the 
direct  deflection  method  is  employed. 

In  brief,  this  consists  of  the  following  steps : 

First.  The  deflection  produced  in  a  galvanometer  by  a  cur- 
rent from  a  battery  through  a  known  resistance,  usually 
100,000  ohms,  is  determined,  whence  is  calculated  the  resist- 
ance through  which  this  same  battery  would  produce  a  deflec- 
tion of  one  point  using  the  unity  shunt.  This  is  expressed  in 
megohms  and  is  called  the  galvanometer  "  constant "  under 
the  conditions. 

Second.  The  deflection  produced  by  the  current  from  the 
same  battery  through  the  insulation  of  the  cable  is  deter- 
mined, whence,  from  "  First,"  the  corresponding  number  of 
megohms  is  calculated. 

Third.  This  multiplied  by  the  length  of  the  cable  in  miles 
and  corrected  for  temperature  gives  the  required  insulation 
resistance  per  mile. 

This  testing  can  be  made  most  satisfactorily  on  dry  days, 
but  a  close  adherence  to  the  instructions  herein  given  relative 
to  the  preparation  of  the  cable  ends,  the  insulation  of  the 
cable  lead  and  of  the  battery,  and  the  drying  out  of  the  test 
room  and  instruments  should  enable  satisfactory  work  to  be 

11003°— 12 8 


94  SUBMARINE    MINING. 

done  under  adverse  conditions  of  weather  or  climate.  The 
following  apparatus  is  required:  Reflecting  galvanometer, 
universal  shunt,  special  testing  key,  100,000-ohm  resistance 
box,  battery  of  dry  cells  giving  approximately  100  volts,  and 
stop  watch. 

Figure  16  shows  diagrammatically  the  arrangement  of  the 
apparatus  for  testing  a  reel  of  cable.  As  a  rule  the  instru- 
ments should*  be  so  placed  that  one  person  may  manipulate 
the  key  and*  the  shunt  while  at  the  same  time  observing  the 
galvanometer. 

The  100,000-ohm  box,  as  a  protection  to  the  galvanometer 
in  testing,  is  always  kept  in  the  circuit  and  its  value  should  be 
subtracted  from  the  resistance  determined,  except  in  the  case 
of  high  insulation  resistance  when  it  will  not  be  necessary 
to  make  the  subtraction. 

The  universal  shunt  is  always  employed  with  the  galva- 
nometer and  is  used  both  to  vary  the  current  through  the  lat- 
ter and  to  protect  it  from  a  violent  throw  at  the  instant  of 
making  or  breaking  the  circuit  at  the  testing  key.  This  last 
is  accomplished  by  having  the  shunt  on  zero  at  such  times. 

The  galvanometer  being  a  very  sensitive  instrument  must 
be  solidly  supported  so  as  to  be  free  from  jars  or  vibrations. 

The  special  testing  key,  shown  diagrammatically  in  the  fig- 
ure, has  its  binding  posts  plainly  marked.  It  is  a  double 
throw  key  and  has  two  positions  upon  each  side.  When 
completely  closed  to  the  right,  the  cable  is  charged  through 
the  galvanometer  from  the  positive  pole;  when  to  the  left, 
from  the  negative  pole  of  the  battery.  In  each  case  the 
deflection  of  the  galvanometer  is  in  the  same  direction.  When 
partly  closed  on  either  side,  the  cable  is  discharged  to  earth 
through  the  galvanometer.  (Note:  It  will  be  observed  that 
the  connections  are  such  that  the  galvanometer  is  always  con- 
nected to  the  cable*core  and  never  to  the  ground.  With  this 
connection,  so  long  as  the  lead  PX  is  free  from  leaks  or 
grounds,  the  galvanometer  measures  only  the  current  actu- 
ally passing  through  the  core  and  not  that  leaking  through 
any  imperfect  insulation  in  the  battery  and  leads.) 

Cable  testing  is  a  very  simple  operation,  but  extreme  care 
is  necessary  in  all  operations. 


SUBMARINE    MINING.  95 

The  following  is  a  detailed  description: 

1.  Preparing  the  cable  for  testing. — 1.  Closely  examine  each 
conductor  end.     Look  particularly  for  unusually  hard  or 
brittle  insulation  and  for  torn,  pinched,  or  punctured  insula- 
tion, especially  near  the  ends  of  the  armor  wires.     If  any  of 
the  ends  are  not  in  perfect  condition,  cut  off  enough  cable  to 
secure  good  ends.     (Caution. — Do  not  cut  off  more  than 
enough  to  secure  good  ends,  for  after  three  or  four  tests  it 
may  be  necessary  to  unreel  the  whole  cable  to  secure  enough 
of  the  inner  end  above  water.) 

2.  Verify  the  tagging.     Remember  that  the  "  shore  end  "  is 
the  end  from  the  outer  coils  on  the  reel  and  is  numbered 
clockwise.     The  other  end  is  numbered  contraclockwise. 

3.  The  "  ground  "  should  be  made  by  taking  several  turns 
of  bare  copper  wire  around  the  armor  of  the  cable  to  be  tested 
and  soldering  them  in  position.     One  such  ground  in  each 
tank  is  sufficient.     Whenever  "  ground  "  or  "  earth  "  is  sub- 
sequently spoken  of,  this  ground  in  the  tank  is  meant,  and 
not  a  connection  to  ground  at  some  point  outside  the  tank. 

4.  The  leads  PX  and  BY  (fig.  16)  should  be  of  loading 
or  other  heavily  insulated  wire.     They  must  be  carefully 
insulated  from  each  other,  from  the  ground,  and  from  the 
walls  or  other  parts  of  buildings.     This  is  especially  true  of 
the  cable  lead  PX.     In  damp  weather  porcelain-knob  insu- 
lators and  porcelain  tubes    (the  latter  for  use  in  passing 
through  walls  or  partitions)  may  not  be  sufficient  to  afford 
proper  insulation  for  the  cable  lead.     In  such  case  the  latter 
should  be  suspended  in  the  air  from  the  testing  switch  to  the 
cable  tank  by  means  of  several  chains  of  paraffined  porcelain 
insulators  suspended  by  marline  or  protective  tape  which  has 
been  boiled  in  paraffin.     These  suspensions  should  be  in  each 
case  under  cover  and  should  be  kept  as  dry  as  possible.     The 
length  of  the  leads  is  immaterial.     If  loading  wire  is  used, 
the  distance  between  supports  should  be  short  (not  over  50 
feet) ,  as  this  wire  stretches  considerably  from  its  own  weight, 
pulling  out  the  insulation  and  giving  a  very  thin  wall,  par- 
ticularly at  points  of  support.     Extreme  care  should  be  taken 
to  tighten  up  on  the  knob  insulators,  in  case  they  are  used, 
just  enough  to  hold  the  wire  without  pinching  the  insulation. 


96  SUBMARINE   MINING. 

5.  Using  a  double  connector,  join  the  lead  BY  to  the  ground 
wire  on  the  cable  above  the  surface  of  the  water.     Put  a  con- 
nector on  the  end  of  the  other  lead  so  that  it  can  be  readily 
attached  in  turn  to  each  conductor. 

6.  Any  protective  covering,  such  as  armor,  jute,  etc.,  should 
be  removed  from  the  ends  of  the  conductors  for  a  distance  of 
about  12  inches,  thus  laying  the  insulation  coating  bare. 
This  latter  should  not  be  handled  and  must  be  kept  scrupu- 
lously clean.     With  a  clean  dry  knife  prepare  each  conductor 
of  the  cable  to  be  tested  by  cutting  off  about  1  inch  of  the 
insulation  from  each  end  of  the  wire  and  then  tapering  the 
end  of  the  insulation  for  about  1  inch,  leaving  a  perfectly 
clean  surface.     In  damp  weather  dip  each  end  of  each  con- 
ductor into  melted  paraffin   (not  boiling,  but  heated  above 
212°  F.).     Secure  one  end  of  the  cable  so  that  it  is  well  sep- 
arated from  the  surrounding  objects  and  separate  the  con- 
ductors so  that  no  ends, are  touching. 

7.  Take  one  strand  of  a  loading  wire  about  4  feet  long 
and  wrap  it  two  or  three  times  around  the  projecting  copper 
end  of  each  conductor  at  the  other  end  of  the  cable,  then 
connect  it  to  earth.     See  that  the  conductors  at  this  end  are 
dry.     Leave  the  lead  PX  disconnected  and  suspended  in 
the  air. 

II.  Setting  up  the  testing  apparatus. — 1.  Select  a  light,  dry 
room  as  near  the  cable  tank  as  practicable. 

2.  Use  dry  cells  for  the  battery.  The  voltage  of  the  bat- 
tery should  be  such  as  to  give  a  full  scale  deflection  of  the 
galvanometer  through  the  resistance  employed  for  taking  the 
constant  (with  shunt  at  jinxr)-  Large  galvanometer  throws 
are  essential  for  reliable  results. 

Set  up  the  cells  on  shelves  in  a  small  closed  closet  or  box, 
with  narrow  strips  of  wood  or  heavy  cardboard  laid  between 
each  row  of  cells,  lengthwise  and  crosswise.  The  height  of 
each  strip  should  be  about  half  the  height  of  a  cell,  so  that 
the  two  layers  of  strips  will  come  nearly  to  the  tops  of  the 
cells  and  keep  them  well  separated.  Wire  the  cells  in  series 
and  bring  the  terminals  out  to  a  double-pole  single-throw 
switch,  which  should  be  on  a  heavy  porcelain  or  slate  base 


SUBMAKINE   MINING.  97 

and  rated  for  at  least  250  volts.  (It  may  be  found  desirable 
to  install  some  electric  lamps  in  the  closet  to  keep  the  battery 
dry.) 

If  difficulty  is  experienced  in  eliminating  grounds  from  the 
battery  set  up  in  this  manner,  the  battery  box  should  be  sus- 
pended in  air  by  means  of  chains  of  paraffined  cleats. 

3.  Set  up  the  galvanometer  on  a  pier  or  on  a  window  sill 
if  the  building  is  of  masonry.     It  should  be  insulated  by 
placing  its  feet  on  a  slate  or  ebonite  slab,  or  in  glass  insu- 
lators.    Remove  the  cover.     Adjust  the  level  until  the  sus- 
pended coil  hangs  freely.     Maneuver  the  suspended  coil,  by 
means  of  the  knob  at  the  top  of  the  tube,  until  its  face  is 
parallel  with  the  face  of  the  instrument.     Then  adjust  the 
level  until  the  upper  suspension  hangs  in  the  center  of  the 
supporting  tube,  and  the  air  gap  between  the  coil  and  arma- 
ture is  symmetrical.     Replace  the  cover.     Put  on  the  scale 
and  the  telescope.     Turn  the  mirror  so  that  it  reflects  the  0 
of  the  scale  approximately,  getting  exact  adjustment  by  mov- 
ing the  scale.     Be  careful  (particularly  in  dry  weather)  not 
to  touch  the  glass  of  the  cover  or  to  do  anything  which  will 
produce  a  static  charge  on  the  glass. 

The  galvanometer  scales  are  usually  graduated  in  equal 
divisions  corresponding  to  1  millimeter  on  the  circum- 
ference of  a  circle  whose  radius  is  1  meter.  Each  tenth 
division  is  usually  marked  with  a  number.  This  number  is 
sometimes  1  instead  of  10,  2  instead  of  20,  and  so  on.  The 
number  of  divisions  to  read  and  record  is  the  number  of 
smallest  (millimeter)  divisions.  Do  not  try  to  read  closer 
than  \  of  one  division.  The  larger  the  throw  the  less  the 
personal  error.  No  accurate  conclusion  can  be  drawn  from 
a  very  small  throw. 

4.  Place  a  table  or  low  shelf  conveniently  to  one  side  and 
place  the  shunt,  the  testing  key,  the  T^  megohm  box,  and  a 
voltmeter  on  it.     The  apparatus  should  be  insulated  by  an 
ebonite  or  slate  slab,  or  glass  insulators.     Fasten  the  shunt 
and  the  key  securely  to  the  table  or  the  shelf.     (The  use  of 
paraffin  paper  for  insulating  instruments  is  a  makeshift  at 
best.     It  soon  gets  soiled  and  creased,  then  it  has  to  be 
replaced.) 


98  SUBMARINE   MINING. 

The  use  of  lamps  to  keep  the  apparatus  dry  may  be  desir- 
able, or  it  may  be  found  convenient  to  expose  the  apparatus 
to  the  sun  for  a  few  minutes  before  beginning  the  test  on  any 
day.  The  use  in  the  testing  room  of  a  small  stove  or  of  a 
gasoline  torch  for  two  or  three  hours  before  the  beginning  of 
the  testing  will  ordinarily  prove  very  advantageous. 

5.  Wire  up  as  in  figure  16,  except  that  the  leads  from  the 
testing  key  should  be  carried  to  the  battery  through  the 
double-pole  single- throw  switch  above  referred  to.  (The 
battery  switch  should  be  opened  whenever  any  connections 
are  made  or  altered.)  All  leads  used  in  connecting  up  the 
instruments  should  be  of  heavy  copper,  and  stiff  enough  to 
hold  permanently  any  shape  to  which  they  are  bent.  They 
should  be  supported  at  points  of  connection  only,  and  should 
not  lie  on  the  table  or  within  an  inch  of  each  other. 

III.  Testing  the  insulation  of  the  apparatus. — 1.  Voltmeter 
test  of  battery  insulation. — This  is  a  rough  test,  but  should 
be  included.  A  serious  ground  can  be  much  more  quickly 
located  with  a  voltmeter  than  with  the  galvanometer. 

(a)  Disconnect  the  battery  leads  at  the  battery  switch ;  con- 
nect +  lead  of  battery  to  +  post  of  the  voltmeter;  connect 
the  B  end  of  the  lead  BY  to  —  post  of  the  voltmeter ;  —  lead 
of  the  battery  should  be  in  the  air.     Close  the  voltmeter 
switch  and  read. 

(b)  Disconnect  the  voltmeter.     Connect   —   lead   of  the 
battery  to  —  post  of  the  voltmeter.     Connect  the  B  end  of 
the  lead  BY  to  +  post  of  the  voltmeter;  -f  lead  of  the  bat- 
tery should  be  in  the  air.     Close  the  voltmeter  switch  and 
read. 

If  any  deflection  is  obtained  in  either  case,  the  battery 
or  its  connections  are  grounded.  Locate  and  remove  the 
ground.  (See  Foster  or  some  other  practical  handbook.) 

2.  Testing  the  battery  voltage. — Connect  the  voltmeter 
across  the  battery  terminals.  Read  and  record  the  voltage. 
(If  there  is  no  voltmeter  available  which  will  read  as  high 
as  the  battery  voltage,  take  the  voltage  of  the  battery  in  sec- 
tions and  add,  or  make  a  multiplier  of  one  of  the  resistance 
coils  in  the  •£$  megohm  box.) 


SUBMARINE    MINING.  99 

3.  Testing  the  battery  and  the  apparatus  for  grounds  with 
the  galvanometer. — With  a  camel's-hair  brush  go  over  all 
the  instruments  and  carefully  remove  dust.     See  that  the 
instruments  and  connections  are  dry.     Do  not  blow  on  the 
instruments. 

Open  the  battery  switch.  Connect  the  battery  leads  to  the 
battery  switch.  Disconnect  lead  PX  at  P  and  connect  the 
earth  leads  BY  and  EY  to  the  key  at  "  cable  post:'  ( Y  is 
grounded.)  Both  battery  leads  are  left  connected  to  the  key. 
The  shunt  should  be  on  0.  Close  the  battery  switch.  Close 
the  testing  key  to  the  right.  Turn  the  shunt  gradually  to 
the  unity  post.  The  galvanometer  deflection  should  be  zero. 
Turn  the  shunt  to  0.  Reverse  the  testing  key.  Turn  the 
shunt  to  the  unity  post.  The  deflection  should  be  zero.  If 
any  deflection  is  obtained,  there  is  a  ground  in  the  battery, 
the  apparatus,  or  the  connections.  The  tesft  of  the  cable 
should  not  proceed  if  a  deflection  is  obtained  in  either  posi- 
tion of  the  key. 

In  reporting  the  voltage  +  to  earth  and  —  to  earth  as 
"  zero  "  on  form,  it  will  be  understood  that  this  means  zero 
using  the  galvanometer,  as  herein  described. 

4.  Insulation  of  leads. — Turn  the  shunt  to  0.     Open  the 
battery  switch.     Connect  the  earth  leads  BY  and  E Y  to  their 
proper  posts.     Connect  the  cable  lead,  PX,  to  "  cable  "  post. 
See  that  the  cable  tank  ends  of  the  lead  PX  is  disconnected 
at  X  and  suspended  in  the  air.     Close  the  battery  switch. 
Close  the  key  and  turn  the  shunt  to  the  unity  post.     Deflec- 
tions should  be  as  small  as  possible  and  in  any  case  must  be 
steady  and  uniform  for  several  trials.     Turn  the  shunt  to  0. 
Reverse  the  key,  stopping  at  the  discharge  position.     Turn 
the  shunt  to  the  unity  post  and  wait  until  the  galvanometer 
rests  at  0,  indicating  that  the  leads  are  discharged.     Turn  the 
shunt  to  0.     Close  the  key  all  the  way  down.     Turn  the  shunt 
to  the  unity  post.     The  deflection  should  not  differ  materially 
from  that  noted  above.     If  there  is  a  deflection,  the  trouble  is 
in  the  lead  PX  or  its  connections.     Go  over  these,  carefully 
examining  for  dust  and  moisture  and  noting  particularly  the 
proximity  of  all  wires  of  opposite  potential  which  cross  or 
lie  near  each  other.    If  there  is  a  small  deflection  which  can 


100  SUBMAKINE   MINING. 

not  be  removed,  a  correction  must  be  applied  subsequently 
to  the  deflection  obtained  in  the  test  for  the  insulation  resist- 
ance of  the  conductor. 

Using  proper  care,  there  are  very  few  days  when  perfect 
insulation  of  the  instruments  can  not  be  secured.  The  lead 
leakage  with  well-insulated  wire  put  up  properly  will  be 
noticed  rarely. 

5.  Use  of  Price  guard-wire. — As  an  additional  precaution 
against  surface  leakage  across  the  insulation  at  the  ends  of 
the  conductor  it  will  sometimes  be  advisable  to  install  an 
additional  lead  (not  necessarily  as  carefully  insulated  as 
PX)  running  from  the  testing  switch  to  the  cable  under 
test.  This  lead  should  be  connected  in  at  the  testing  switch 
to  the  post  carrying  the  lower  blade  between  "  D  "  and  "  C  " 
(fig.  16) ;  the  tank  end  should  be  bare  of  insulation  for  a 
sufficient  distance  to  enable  the  bare  wire  to  be  wrapped 
firmly,  without  pinching,  around  the  insulation  at  each  end 
of  the  particular  conductor  under  test,  just  below  the  tapered 
portion. 

The  potential  difference  between  the  cable  core  and  this 
guard-wire  is  thus  made  practically  nil,  so  that  any  leakage 
will  be  from  the  guard-wire  to  the  tank,  consequently  this 
leakage  will  not  be  measured  by  the  galvanometer. 

IV.  Take  the  galvanometer  constant  as  follows:  Open  the 
battery  switch. 

With  a  short  piece  of  wire  connect  the  hinge  post  of  the 
testing  key  marked  "  cable  "  to  either  "  earth  "  post  of  the 
key,  the  leads  to  the  cable  tank  being  disconnected  at  E,  B, 
and  P.  Turn  the  shunt  to  0.  Examine  the  -^  megohm  box 
and  see  that  all  the  resistance  coils  are  in  the  circuit.  Close 
the  battery  switch  and  the  testing  key.  Turn  the  shunt  to 
the  ToVc  post.  Watch  the  swing  of  the  galvanometer  and 
when  it  has  come  to  rest,  read  and  record.  Turn  the  shunt 
to  0.  The  galvanometer  should  return  exactly  to  0.  If  it 
does  not,  readjust  and  repeat  until  it  does.  The  galvanome- 
ter constant  is  numerically  equal  to  the  total  throw  in  smallest 
divisions  of  the  scale  multiplied  by  100.  Remove  the  con- 
necting wire  and  replace  the  leads  to  the  tank. 


SUBMARINE   MINING.  101 

If  at  any  subsequent  time  during  the  test  the  galvanometer 
adjustment  is  disturbed — that  is,  if  it  does  not  return  accu- 
rately to  zero  when  the  shunt  is  at  0 — the  constant  should  be 
redetermined. 

V.  Testing  the  cable. — 1.  See  that  the  testing  key  is  open 
and  the  shunt  at  0.  Connect  the  earth  lead  to  ground  on 
the  cable  armor.  Remove  the  earth  connection  from  No.  1 
conductor  and  connect  the  cable  lead  to  this  conductor;  in 
wet  weather  the  connector  joint  should  be  dipped  in  melted 
paraffin.  (In  using  paraffin  to  insulate  joints  or  ends  bring 
it  just  above  212°  F.  to  evaporate  any  moisture  present. 
It  should  not  be  boiling.  The  paraffin  coating  should  be  at 
least  as  thick  as  the  rubber  insulation  and  extend  back  over 
the  rubber  for  an  inch  or  more.) 

2.  Close  the  testing  key  to  the  left  (-f-  to  earth),  stopping 
at  the  discharge  position,  and  turn  the  shunt  to  the  unity 
post.     There  should  be  no  deflection.     If  there  is,  it  is  due 
either  to  a  charge  on  the  cable,  which  will  disappear  after  a 
moment,  or  to  earth  currents.     (It  is  assumed  that  the  test- 
ing apparatus  has  been  thoroughly  tested  for  insulation.) 
If  due  to  earth  currents,  the  conductor  is  probably  a  poor 
one.     Earth  currents  are  readily  recognizable  by  their  fluc- 
tuating character.    Before  assuming  that  the  trouble  can  not 
be  removed,  the  joint  between  the  lead  and  the  conductor 
should  be  examined  again.     Moisture  on  the  cable  end  will 
give  a  path  for  earth  currents.     Note  the  value  and  direc- 
tion of  the  throw  of  the  galvanometer  and  record  it. 

3.  Turn  the  shunt  to  0,  close  the  testing  key  all  the  way 
down  (-f-  to  earth),  noting  the  time  to  the  second,  or  start- 
ing the  stop  watch  at  the  same  time,  if  one  is  available.     The 
time  must  be  accurately  noted.    The  insulation  resistance  at 
the  end  of  one  minute's  electrification  is  the  resistance  to  be 
reported. 

4.  When  35  seconds  have  elapsed,  turn  the  shunt  to  the 
T tfW-post  and  watch  the  galvanometer  throw ;  if  small,  move 
the  shunt  successively  to  the  rfo-post,  to  the  TVpost,  and  to 
the  unity  post.     This  operation  must  be  completed  before  45 
seconds  have  elapsed  from  the  time  the  key  was  closed.    With 


102  SUBMARINE    MINING. 

good  cable  the  unity  post  will  always  be  reached  without 
danger  of  throwing  the  galvanometer  reading  off  the  scale. 
Remember  that  each  successive  post  should  give  10  times 
the  throw  of  the  preceding  post. 

5.  At  the  end  of  one  minute  read  the  deflection,  correct  for 
the  leakage  of  the  leads  and  the  earth  currents,  and  record. 
(See  example  following.) 

6.  At  the  end  of  two  minutes  read  the  deflection,  correct 
and  record  it.    For  good  cable  it  should  be  less  than  the  de- 
flection observed  at  the  end  of  one  minute. 

7.  Turn  the  shunt  to  0,  and  reverse  the  key,  stopping  at  the 
discharge  position.     Turn  the  shunt  on  gradually  until  the 
unity    post    is   reached    and   wait   until   the   reading  is   0, 
indicating  that  the  conductor  is  discharged.     If  earth  cur- 
rents are  present,  0  will  not  be  reached  or  wrill  be  passed.    In 
this  case  proceed  as  before  described.     A  submarine-mine 
cable  conductor  a  mile  long  will  discharge  ordinarily  in 
about  three  minutes. 

8.  Turn  the  shunt  to  0,  stop  and  start  the  stop  watch;  at 
the  same  time  close  the  key  all  the  way  down  (—  to  earth). 

9.  After  35  seconds,  start  turning  the  shunt,  ceasing  at  45 
seconds.     ( See  paragraph  4,  above. ) 

10.  At  the  end  of  one  minute  read  the  deflection,  correct 
and  record  it.     For  good  cable  it  should  be  substantially 
the  same  as  the  deflection  observed  at  the  end  of  one  minute 
with  -f  of  the  battery  to  earth. 

11.  Turn  the  shunt  to  0,  and  reverse  the  key,  stopping  at 
the  discharge  position. 

12.  Disconnect  No.  2  conductor  from  ground.     Disconnect 
No.  1  from  the  lead  and  connect  up  No.  2.     Connect  No.  1  to 
ground.     It  is  not  necessary  to  wait  for  No.  1  to  be  dis- 
charged completely  before  disconnecting  it. 

13.  Proceed  with  No.  2  as  with  No.  1  and  repeat  with  each 
conductor. 

14.  On  the  completion  of  the  test  all  conductor  ends  should 
be  carefully  taped. 

15.  To  determine  the  correct  value  of  the  insulation  resist- 
ance it  is  essential  that  the  negative  pole  of  the  battery  be 


SUBMARINE    MINING.  103 

connected  to  the  core  of  the  cable,  otherwise  the  products  of 
electrolysis  will  tend  to  seal  up  any  fault  which  may  exist  and 
will  cause  the  conductor  to  appear  better  than  it  really  is. 
With  the  negative  pole  of  the  battery  to  the  core  the  tendency 
is  to  deposit  copper  on  the  core  and  thus  to  lay  bare  any  fault. 
The  insulation  resistance  of  any  conductor  is  therefore  found 
by  multiplying  the  corrected  deflection  at  the  end  of  one 
minute,  with  +  of  battery  to  earth,  by  the  denominator  of 
the  shunt  used,  and  then  dividing  the  galvanometer  constant 
by  this  product.  The  resistance  of  the  TVmegohm  box  is 
neglected  unless  the  insulation  resistance  determined  is  very 
low,  say,  under  1  megohm,  when  the  100,000  ohms  should 
be  subtracted  from  the  above  quotient. 

16.  To  determine  the  insulation  resistance  per  mile  at  60° 
F.,  multiply  the  actual  insulation  resistance  found  by  the 
length  of  the  cable  in  miles,  and  this  result  by  the  multiplier 
furnished  by  the  torpedo  depot  for  the  particular  make  of 
cable,  corresponding  to  the  temperature  of  the  water  in  the 
tank  observed  during  test. 

Example. — Leakage  of  the  leads  found  to  be  one-half 
division.  Earth  currents  found  to  give  1J  divisions  in  a 
negative  direction  from  0  of  the  scale.  Galvanometer  throw 
at  the  end  of  one  minute  (+  to  earth),  15  divisions.  The 
corrected  deflection  is,  15— J-|-1J=16  divisions. 

The  galvanometer  constant  (450  divisions  through  T^ 
megohm,  shunt  at  ioW))  45,000  megohms.  That  is,  the 
battery  will  give  -^  °f  450  divisions=45  through  1  megohm, 
the  shunt  at  T^TT  >  or,  what  is  the  same  thing,  one  division 
through  45  megohms,  the  shunt  at  y^^  ;  therefore  with 
the  shunt  at  unity  the  battery  will  give  one  division  through 
45X1,000—45,000  megohms.  The  insulation  resistance^- 
45,000-^-16=2,813  megohms.  If  the  cable  is  three-fourths 
mile  long,  the  insulation  resistance  in  megohms  per  mile  is 
2,813X1=2,110  megohms. 

Manufacturer,  Safety  Insulated  Wire  &  Cable  Co. 

Temperature  of  water  in  tank,  80°  F. 


104  SUBMARINE   MINING. 

Multiplier,  1.7056;  2,110X1.7056=3,599  megohms  insula- 
tion resistance  per  mile  at  60°  F.  This  result  is  recorded 
on  the  form. 

VI.  Copper  resistance. — 1.  The  drop  of  potential  method  is 
quicker  than  the  bridge  method  under  the  usual  conditions 
and  should  be  used  if  the  apparatus  is  available. 

Apparatus  required. — (a)  Source  of  power  (110  volts 
D.  C.  lighting  circuit,  casemate  battery  or  generator)  ;  (b)  a 
double-pole  single-throw  switch  to  which  the  power  leads  are 
attached;  (c)  a  bank  of  ten  110-volt  lamps  in  parallel;  (d)  a 
D.  C.  ammeter  of  not  more  than  0-25  scale;  (e)  a  D.  C. 
voltmeter,  0-150  scale. 

Place  the  lamp  bank  and  the  ammeter  in  one  side  of  the 
power  line  from  the  switch  to  the  conductor,  and  the  other 
end  of  the  conductor  to  the  other  side  of  the  power  line. 
Connect  the  voltmeter  across  the  ends  of  the  cable  so  as  to 
measure  the  drop  of  potential  between  the  ends  of  the  con- 
ductor being  tested.  Close  the  switch,  take  simultaneous 
readings  on  the  voltmeter  and  the  ammeter  and  calculate  the 
resistance.  With  the  apparatus  described  a  conductor  1  mile 
long  will  receive  about  2J  amperes  and  show  a  drop  of  about 
50  volts.  The  lamps  are  inserted  as  a  safety  precaution.  In 
no  case  should  the  current  through  the  conductor  exceed  6 
amperes.  If  the  cable  has  been  tested  for  insulation  resist- 
ance and  all  the  conductors  show  high  insulation,  the  lamps 
are  not  necessary,  provided  the  cable  is  at  least  a  mile  long. 

2.  The  copper  resistance  found  is  reduced  to  that  at  60°  F. 
by  multiplying  by  the  coefficient  found  in  the  following  table 
with  the  temperature  of  the  water  in  the  tank  at  the  time 
of  the  test  as  an  argument : 


SUBMARINE    MINING. 
Reduction  of  copper  resistance  to  60°  F 


105 


Tem- 
pera- 
ture. 

S 

Tem- 
pera- 
ture. 

8 

Tem- 
pera- 
ture. 

d 

10 

1252 

40 

1.0468 

70 

.9781 

11 

1224 

41 

1.0443 

71 

.9759 

12 

1196 

42 

1.0419 

72 

.9738 

13 

1168 

43 

1.  0395 

73 

.9717 

14 

1141 

44 

1.  0371 

74 

.9695 

15 

1113 

45 

1.0347 

75 

.9674 

16 

1086 

46 

1.0323 

76 

.9653 

17 

1059 

47 

1.0300 

77 

.9632 

18 

.1032 

48 

1.  0276 

78 

.9611 

19 

.1005 

49 

1.  0252 

79 

.9591 

20 

.0978 

50 

1.0229 

80 

.9570 

21 

.0952 

51 

1.0206 

81 

.9549 

22 

.0925 

52 

1.0182 

82 

.9529 

23 

.0899 

53 

1.  0159 

83 

.9508 

24 

.0873 

54 

1.0136 

84 

.9488 

25 

.0846 

55 

1.0113 

85 

.9468 

26 

.0820 

56 

1.0090 

86 

.9448 

27 

.0794 

57 

1.0068 

87 

.9428 

28 

.0769 

58 

1.0045 

88 

.9408 

29 

.0743 

59 

1.0023 

89 

.9388 

30 

.0717 

60 

1.0000 

90 

.9368 

31 

.0692 

61 

.9978 

91 

.9348 

32 

.0667 

62 

.9956 

92 

.9328 

33 

.0641 

63 

.9933 

93 

.9308 

34 

1.0616 

64 

.9911 

94 

.9288 

35 

1.  0591 

65 

.9889 

95 

.9269 

36 

1.0566 

66 

.9867 

96 

.9250 

37 

1.0542 

67 

.9846 

97 

.9231 

38 

1.0517 

68 

.9824 

98 

.9211 

39 

1.0492 

69 

.9802 

99 

.9192 

The  true  length  of  a  cable  should  be  that  of  its  center 
conductor. 

From  the  size  of  the  conductor  and  its  copper  resistance 
the  length  of  the  cable  may  be  computed  by  use  of  the  follow- 
ing wire  table : 

Table  of  resistances  of  pure  copper  wire  at  60°  F. 


Size 
B.&S. 

Dia.in 
mils. 

Ohms  per 
1,000  feet. 

Size 
B.&S. 

Dia.  in 
mils. 

Ohms  per 
1,000  feet. 

1 

289 

0.11999 

16 

51 

3.8880 

2 

258 

.  15130 

17 

45 

4.9030 

3 

229 

.19080 

18 

40 

6.  1827 

4 

204 

.24058 

19 

36 

7.8024 

5 

182 

.30338 

20 

32 

9.  8316 

6 

162 

.38256 

21 

28.5 

12.  397 

7 

144 

.48245 

22 

25.3 

15.  625 

8 

128 

.60831 

23 

22.6 

19.  712 

9 

114 

.76696 

24 

20.1 

24.  857 

10 

102 

.96740 

25 

17.9 

31.  343 

11 

91 

1.21960 

26 

15.9 

39.  535 

12 

81 

1.  5379 

27 

14.2 

49.  839 

13 

72 

1.  9393 

28 

12.6 

62.  848 

14 

64 

2.  4453 

29 

11.3 

79.  250 

15 

57 

3.0134 

30 

10.0 

99.  932 

106  SUBMARINE   MINING. 

The  objections  to  the  use  of  a  bridge  for  measuring  copper 
resistance  are  the  difficulty  of  eliminating  the  resistance  of 
the  plug  contacts  and  the  time  required  to  secure  balance. 
The  resistance  of  the  plug  contacts  may  often  be  as  high  as 
20  ohms,  particularly  if  used  at  the  tank. 

If  the  bridge  is  used  at  all,  it  should  be  placed  in  the  test- 
ing room,  and  the  same  leads  employed  for  testing  insulation 
should  be  used.  The  resistance  of  these  leads  should  first  be 
determined  by  connecting  them  together  and  measuring; 
this  resistance  is  subtracted  from  each  resistance  measured. 

VII.  General. — The  key  to  success  in  cable  testing  is  great 
care  in  every  detail.  The  cable  now  being  furnished  is  all 
tested  with  galvanometers  having  constants  from  200,000  to 
250,000  megohms.  It  has  all  been  accepted  after  most  care- 
ful test.  The  chances  are  that  it  is  good  when  it  arrives  at 
the  post,  unless  it  has  been  mechanically  injured  in  transit, 
which  should  be  ascertained  by  careful  inspection  when  de- 
livered at  the  posit. 

Do  not  accept  a  single  measurement  if  it  shows  low  resist- 
ance, but  repeat  until  certain  of  results.  The  time  between 
trials  on  the  same  conductor  should  be  as  great  as  practicable. 
For  example :  Measurements  showing  low  resistance  made  in 
the  morning  should  be  repeated  in  the  afternoon ;  those  made 
in  the  afternoon  should  be  repeated  the  next  day;  the  con- 
ductor being  connected  to  earth  during  the  interval  between 
tests. 


APPENDIX  NO.  5. 

CARE   AND    PRESERVATION   OF    SUBMARINE   MINE 
MATERIEL. 

Frequent  inspections  of  all  articles  of  submarine  mine 
equipment  should  be  made,  not  only  to  check  up  the  prop- 
erty, but  also  to  determine  the  condition  of  all  materiel, 
and  especially  to  see  if  it  has  been  affected  by  dampness. 
These  inspections  should  be  thorough  and  detailed,  as  only  in 
this  manner  can  there  be  impressed  on  those  directly  charged 
with  the  care  of  the  property  the  importance  of  ventilation, 
dryness,  and  the  proper  use  of  preservatives. 

The  generating  set,  storage  battery,  motor-generators,  case- 
mate transformers,  power  panel,  and  operating  boards  will 
be  installed  in  the  mining  casemate,  and  such  tools,  appli- 
ances, and  materials  as  may  be  used  when  this  apparatus  is  in 
commission  will  also  be  kept  there. 

The  explosive  will  be  kept  in  the  magazines  and  tested  and 
cared  for  in  the  manner  prescribed  in  Appendix  No.  1. 

The  multiple  and  single  conductor  cable  will  be  kept  in  the 
cable  tanks  as*  described  in  Appendix  No.  4. 

All  other  articles  of  equipment  will  ordinarily  be  kept  in 
the  storehouse,  and  a  noncommissioned  officer  will  be  placed 
directly  in  charge.  It  shall  be  his  duty  to  keep  the  materiel 
in  the  best  possible  condition,  using  such  details  from  the 
submarine  mine  detachment  from  time  to  time  as  may  be 
necessary  to  assist  him  in  this  work.  He  shall  check  up  all 
articles  taken  from  the  storehouse  during  practice  and  report 
at  the  end  of  the  day's  work  any  shortage  in  tools  or  appli- 
ances that  he  may  discover. 

Paints  and  oils  should  be  kept  separate  from  other  stores, 
and  the  floor  where  kept  should  be  covered  with  2  or  3  inches 

11003° — 12 9  107 


108  SUBMARINE    MINING. 

of  sand,  to  be  renewed  occasionally.  Sawdust  should  never 
be  used  for  this  purpose.  Cotton  waste  which  has  become 
unfit  for  use  should  be  promptly  burned.  Fuses  must  not  be 
stored  with  other  explosives. 

Gasoline  in  considerable  quantites  should  be  stored  in  tanks 
underground  and  never  inside  of  buildings.  Small  quanti- 
ties should  be  kept  outside  of  buildings  in  some  safe  place. 

When  oil  engines  or  generators  are  out  of  commission, 
their  bright  parts  should  be  covered  with  light  slushing 
oil.  Brass  screw  threads  and  parts  of  tools  that  are  liable 
to  rust  should  be  covered  also.  In  all  cases  the  light  slush- 
ing oil  should  be  applied  in  a  thin  coast,  since  this  is  all 
that  is  necessary  to  give  good  protection.  Before  applying 
the  light  slushing  oil  to  any  surface  it  should  be  thoroughly 
cleaned,  so  as  to  be  free  from  rust,  water,  kerosense,  and 
lubricating  oil,  as  their  presence  will  cause  rusting  under- 
neath the  slushing  oil.  The  protected  surfaces  should  be 
occasionally  inspected  and  the  coating  of  slushing  oil  re- 
newed as  often  as  required. 

Screw  threads  of  mine  cases,  steel  screw  threads  of  com- 
pound plugs,  bolts,  nuts  and  washers,  and  surfaces  of  flat 
joints  should  be  kept  coated  with  the  light  slushing  oil  or  a 
mixture  of  machine  oil  and  graphite. 

No  oils  or  grease  should  ever  be  placed  on  points  where 
metallic  contact  of  electrical  instruments  is  necessary,  nor 
on  india  rubber,  ebonite,  or  slate. 

Mine  cases  should  rest  on  racks  or  skids,  and  where  space 
permits  should  not  be  in  contact  with  each  other.  In  hand- 
ling mine  cases  care  must  be  taken  not  to  damage  the  bails 
and  bolts.  They  should  be  arranged  so  that  the  holes  in  the 
mine  cases  can  be  seen  easily;  these  holes  should  be  fitted 
with  a  wooden  plug  which  has  been  thoroughly  greased  all 
over  its  surface.  New  mine  cases,  if  galvanized,  usually  will 
not  need  painting  until  they  have  been  in  the  water.  When 
taken  from  the  water  they  should  be  thoroughly  dried,  and 
if  they  should  show  signs  of  rust  they  should  be  gone  over 
thoroughly  with  steel  wire  brushes  until  the  rust  is  removed. 
Parts  which  can  not  be  reached  with  the  brush  should  be 
cleaned  with  three-cornered  steel  scrapers.  A  heavy  coat  of 


SUBMARINE    MINING.  109 

red  lead  should  then  be  applied.  Seven  gallons  of  this  paint 
can  be  made  by  mixing  100  pounds  of  red  lead  ground  in  oil 
with  5  gallons  of  raw  linseed  oil.  This  mixture  should  be 
applied  within  two  or  three  weeks  after  mixing.  One  gallon 
of  paint  should  give  10  mine  cases  one  coat.  After  this  coat 
has  been  allowed  to  dry  there  should  be  applied  a  coat  of 
white  lead  toned  down  to  a  neutral  gray.  Seven  gallons  of 
this  paint  can  be  made  by  mixing  100  pounds  white  lead,  2J 
gallons  raw  linseed  oil,  2J  gallons  turpentine,  1  gallon  liquid 
drier,  and  adding  about  1  pound  of  lampblack  to  tone  down 
the  mixture. 

Mines  treated  in  this  way,  if  kept  in  a  dry  storehouse,  and 
not  put  in  the  water,  should  not  require  repainting  for  sev- 
eral years.  Frequent  inspection  should  be  made,  however, 
for  in  handling  the  cases  and  changing  their  positions  on  the 
racks,  it  will  often  happen  that  an  abrasion  will  be  made  in 
the  surface  of  the  paint,  which  if  neglected  may  serve  as  the 
starting  point  of  a  progressive  corrosion,  which  may  extend 
rapidly  under  the  surface  of  the  paint.  Should  loose  paint 
or  rust  be  seen  the  case  should  be  repainted.  A  small  wooden 
mallet  may  be  used  to  tap  the  case  at  all  points  to  loosen 
scales  of  rust  or  paint ;  then  the  surface  should  be  thoroughly 
wire  brushed  or  scraped  and  the  cases  repainted  as  stated 
above.  The  inside  of  mine  cases  must  be  inspected  to  see 
that  the  interior  surfaces  are  kept  free  from  rust. 

Ground  mines  and  ground-mine  buoys  should  be  treated  in 
the  manner  just  described  for  buoyant-mine  cases. 

If  the  oil  engine  has  not  been  painted,  it  should  be  given  a 
priming  coat  of  red  lead  mixed  in  oil.  This  should  be 
rubbed  down  with  pumice  stone  and  two  coats  of  steel- 
colored  paint  applied.  The  second  coat  should  be  rubbed 
down  and  two  coats  of  varnish  then  applied.  After  this  the 
engine  should  not  need  repainting  for  a  couple  of  years. 
When,  however,  repainting  is  necessary,  the  engine  should 
be  rubbed  down  until  all  the  varnish  is  removed  and  a  coat 
of  steel-colored  paint  applied.  This  coat  should  be  rubbed 
until  no  brush  marks  remain,  and  one  or  two  coats  of  varnish 
should  then  be  applied.  The  steel-colored  paint  should  be 
applied  flat;  that  is,  the  color  which  is  ground  in  japan 


110  SUBMARINE  MINING. 

should  be  mixed  with  turpentine.  One  gallon  of  this  paint 
is  more  than  sufficient  to  give  an  engine  two  coats. 

The  motor-generators  and  the  casemate  transformers  usu- 
ally will  not  need  the  priming  coat  of  red  lead,  as  they  come 
from  the  factory  painted.  When  it  is  necessary  to  paint 
them,  one  coat  of  the  steel-colored  paint  and  one  of  varnish 
will  usually  be  found  sufficient. 

Anchors,  distribution  boxes,  junction  boxes,  mooring  sock- 
ets, shackles,  sister  hooks,  and  the  ironwork  of  operating 
boards  and  power  panels  should  be  painted  with  asphaltum 
varnish. 

Paint  brushes  when  new,  and  before /use,  should  be  wrapped 
or  bridled  with  strong  twine  and  soaked  in  water  to  swell. 
After  use  they  should  be  cleaned  with  turpentine  and  put 
away  in  water  to  keep  them  from  drying  and  becoming 
unpliable. 

Large  ropes  should  be  stored  on  skids,  allowing  a  free  cir- 
culation of  air.  Small  ropes  should  be  hung  on  wooden 
pins.  Ropes  should  be  uncoiled  semiannually  in  dry  seasons 
and  stretched  out  for  several  days  to  dry.  Wire  rope  must 
be  stored  in  a  dry  place  where  it  will  not  rust.  Marline- 
covered  wire  rope  should  be  stored  where  there  is  a  fair  cir- 
culation of  air.  The  date  of  receipt  should  be  stenciled  on 
each  reel.  If  not  used  at  the  end  of  five  years  it  should  be 
run  through  a  bath  of  pure  distilled  tar  oil.  This  may  be 
done  by  setting  up  an  empty  reel  20  feet  in  front  of  the  full 
reel  and  placing  a  tub  of  the  tar  oil  midway  between  them. 
As  the  rope  comes  off  the  full  reel  it  is  passed  through  the 
oil  and  the  surplus  oil  slicked  off  with  a  piece  of  burlap, 
thus  returning  the  oil  to  the  bath.  The  freshly  oiled  reel 
will  continue  to  drip  for  several  days,  and  sand  should  be 
put  on  the  floor  under  the  reel  to  take  up  the  excess  oil.  After 
use  in  water  the  marline-covered  rope  should  be  thoroughly 
dried  out  and  then  reoiled  as  above  described. 


APPENDIX  NO.  6. 

INSTRUCTIONS  FOE  MASTERS  OF  MINE  PLANTERS. 

The  matter  contained  in  this  appendix  is  primarily  for 
the  information  of  the  masters  of  those  vessels  which  are 
called  into  service  for  mine-planting  purposes  upon  the  out- 
break or  threatening  of  hostilities. 

The  master  shall  request  to  be  supplied  with  a  copy  of 
Regulations  for  Mine  Planters,  U.  S.  Army. 

To  each  vessel  will  be  assigned  a  coast  artillery  officer,  who 
shall  be  the  commanding  officer  of  the  vessel.  All  orders  for 
the  vessel  shall  be  given  to  and  through  him.  He  shall  have 
general  charge  of  its  business  and  be  responsible  for  the 
proper  care  and  disposition  of  all  stores  aboard,  leaving  to 
the  master  of  the  vessel  the  full  and  unquestioned  control 
and  authority  over  all  matters  for  which  he  is  professionally 
responsible. 

Any  orders  to  be  given  by  the  commanding  officer  concern- 
ing the  vessel  or  its  crew  will  be  given  to  or  through  the 
master,  except  that  when  planting  mines  or  operating  any 
of  the  mining  appliances  or  machinery  aboard  the  vessel,  the 
commanding  officer,  or  an  officer  designated  by  him,  may 
give  instructions  directly  to  any  of  the  vessel's  officers  or  to 
members  of  the  vessel's  crew  who  have  duties  directly  con- 
nected with  the  mining  work. 

The  duties  and  responsibilities  of  the  master  of  a  vessel 
engaged  in  submarine  mine  work  do  not  differ  materially 
from  those  devolving  upon  him  when  his  vessel  is  otherwise 
employed.  With  respect  to  every  duty  the  vessel  may  be 
called  upon  to  perform,  it  may  be  stated  that  explicit  direc- 
tions as  to  where  the  vessel  is  to  go  and  just  what  maneuvers 
it  is  to  execute  in  the  mine  field  will  be  given  by  the  officer 

ill 


112  SUBMARINE   MINING. 

aboard,  and  it  is  then  incumbent  upon  the  master  to  execute 
the  maneuver  according  to  his  best  judgment. 

The  duties  that  vessels  employed  as  mine  planters  are  likely 
to  be  called  upon  to  perform  are  as  follows: 

1.  To  lay  out  the  mine  fields. 

2.  To  lay  the  multiple  cable. 

3.  To  plant  mines. 

4.  To  take  up  mines  (including  replacing  defective  mines 
by  good  ones  where  necessary). 

5.  To  take  up  the  cable. 

The  commanding  officer  of  the  vessel  is  responsible  for  the 
proper  equipment  of  the  vessel  with  the  necessary  apparatus 
for  mine  planting,  for  the  loading  of  all  the  materiel  prior 
to  the  planting,  and  for  the  method  of  procedure  under  the 
above  heads. 

The  master  of  the  vessel  will  carry  out  the  orders  of  the 
commanding  officer  and  is  concerned  only  in  the  handling  of 
his  boat  to  prevent  accidents  to  it  and  to  the  boats  engaged 
in  the  planting. 

The  following  precautions  will  be  observed  by  masters : 

1.  If  current  flows  across  the  mine  field  the  planting  vessel, 
to  avoid  accidents,  should  always  pass  on  the  downstream 
side  of  the  yawl  boat  holding  the  measuring  line. 

2.  The  greatest  care  should  be  taken  that  the  measuring 
line  and  buoy  ropes  are  not  caught  in  the  propellers.     If 
the  vessel  has  twin  screws,  the  upstream  propeller  should 
be  stopped  as  soon  as  the  measuring  line  has  been  passed 
to  the  marking  boat.     In  all  cases  a  man  with  a  boat  hook 
should  be  posted  near  the  anchor  davits  and  another  amid- 
ships, to  hold  the  measuring  line  above  the  water  and  clear 
of  the  sides  of  the  vessel.     Keg  buoys,  and  as  much  of  the 
buoy  rope  as  possible,  should  be  held  on  the  rail  near  the 
stern,  letting  the  rope  pay  out  slowly  and  under  tension, 
until  the  propellers  are  past  the  rope,  then  the  keg  and  the 
remainder  of  the  rope  may  be  thrown  overboard. 

3.  A  general  rule  is  never  to  back  either  propeller  when 
buoy  ropes,  measuring  lines,  or  cables  are  being  handled 
overboard  at  or  near  the  stern  of  the  vessel. 


SUBMAKINE   MINING.  113 

4.  If  it  becomes  absolutely  necessary  to  reverse  the  pro- 
pellers when  paying  out  cable,  men  paying  it  out  must  haul 
it  in  taut  and  keep  it  above  the  wheel  and  clear  of  it.     The 
planting  vessel  should  not  pass  nearer  than  25  feet  to  the  dis- 
tribution-box boat  when  cable  is  leading  out  from  the  latter, 
nor  should  it  pass  over  any  cable,  if  it  can  be  avoided,  if  the 
depth  is  less  than  16  feet. 

5.  The  vessel  should  proceed  after  passing  the  distribution- 
box  boat  on  such  a  course  that  cable  will  pay  off  smoothly 
without  becoming  entangled.     If  a  cable  becomes  fouled  and 
entangled,  the  end  should  be  "let  go"  at  once  at  the  dis- 
tribution-box boat — the  planter  should  proceed  on,  not  stop 
nor  back  its  propellers.     Mine  cable  should  never  be  made 
fast  in  the  distribution-box  boat  until  after  a  mine  is  dropped. 
It  is  much  better  to  drop  the  mine  out  of  position  than  to  en- 
danger the  propellers  of  the  vessel.     The  propeller  nearest 
the  distribution  box  should  be  stopped  the  moment  the  bow 
of  the  vessel  passes  the  distribution-box  boat  on  its  course  to 
drop  a  mine. 

6.  If,  in  planting,  the  vessel  moves  against  the  direction  of 
the  current,  there  is  little  danger  of  overturning  the  distribu- 
tion-box boat  if  ordinary  caution  is  observed.     Should  it  be 
necessary  to  plant  against  a  cross  current  or  with  it,  it  is  best 
to  pass  the  cable  end  to  the  distribution-box  boat  by  a  launch 
or  small  boat.     In  this  way  the  planter  need  not  pass  within 
50  or  75  yards  of  the  boat. 

7.  To  avoid  getting  foul  of  the  buoy  rope  or  mine  after 
the  mine  is  dropped,  the  helm  should  be  put  over  so  as  to 
throw  the  stern  away  from  the  mine.     The  vessel  should  be 
under  good  headway  so  that  the  propellers  may  be  stopped 
until  they  are  well  past  the  buoy  and  buoy  ropes  of  the  mine. 
These  points  are  important;   failure  to  observe  them  will 
result  disastrously. 

In  laying  multiple  cable,  the  course  of  the  vessel  invariably 
should  be  against  the  current.  Rather  than  lay  cable  with 
the  current  it  is  advisable  to  postpone  laying  the  cable  until 
a  change  of  the  tide  causes  a  favorable  direction  of  current. 
In  the  end,  time  will  be  saved  by  waiting.  Cable  should  pay 


114  SUBMARINE   MINING. 

off  on  the  upstream  side  of  the  vessel  if  any  cross  current  is 
running.  All  care  should  be  taken  that  the  cable  does  not  get 
caught  in  the  vessel's  propellers.  This  is  of  the  greatest  im- 
portance. 

As  the  cable  pays  out  over  a  chock  near  the  bow  of  the  ves- 
sel a  man  should  stand  by  with  a  3-inch  strap  in  readiness  to 
stop  the  cable  should  it  be  necessary,  and  two  men  should 
manipulate  brakes  to  prevent  the  cable  from  paying  out  too 
rapidly.  This  is  especially  necessary  if  the  water  is  deeper 
than  50  feet. 

Especial  care  is  necessary  in  planting  mines  to  avoid:  (a) 
Colliding  with  yawl  or  distribution-box  boat;  (b)  picking  up 
cable  in  the  propeller;  (c)  getting  the  mine  cable  tangled; 
(d)  drifting  over  the  mine  after  it  is  dropped. 


APPENDIX  NO.  7. 
MANUAL  FOR  SMALL  BOATS. 

The  left-hand  side  of  a  boat  or  ship,  looking  toward  the 
bow,  is  the  port  side,  and  the  other  is  the  starboard  side. 
The  men  who  row  on  the  port  side  are  called  the  port  oars 
and  those  rowing  on  the  starboard  side  are  called  the  star- 
board oars. 

Boats  are  called  single  or  double  banked,  according  as  they 
have  one  or  two  oarsmen  to  a  thwart. 

Thwarts  are  the  seats  on  which  the  crew  sits;  the  space 
abaft  the  after  thwart  is  called  the  stern  sheet. 

Floorings  and  gratings  are  the  bottom  boards  of  a  boat. 
They  prevent  the  weight  from  bearing  directly  upon  the 
planking. 

The  gunwale  of  a  boat  is  the  upper  rail. 

The  yoke  is  an  athwartship  piece  of  wrood  or  metal  fitting 
over  the  rudderhead. 

Yoke  lanyards  are  the  small  lines  made  fast  to  the  ends  of 
the  yoke,  by  which  the  rudder  is  turned  and  the  boat  steered. 

The  stem  is  the  upturned  portion  of  the  keel  at  the  bow  of 
the  boat,  to  which  the  forward  ends  of  the  planks  are  secured. 

Oars  are  said  to  be  double-banked  when  two  men  pull 
one  oar. 

The  blade  of  an  oar  is  the  broad  flattened  part.  The 
handle  is  the  small  part  of  an  oar  on  the  inboard  end  of  the 
loom,  which  the  oarsman  grasps  when  pulling.  The  loom 
is  the  portion  of  an  oar  extending  from  the  blade  to  the 
handle.  The  leather  is  the  portion  of  an  oar  which  rests  in 
the  rowlock.  This  is  sometimes  covered  with  canvas,  but  is 
usually  covered  with  leather ;  hence  the  name. 

Feathering  is  the  term  applied  to  the  operation  of  turning 
the  blades  nearly  flat  to  the  water  after  the  stroke,  with  the 
upper  edge  turned  forward,  especially  valuable  in  rowing 
against  a  head  wind. 

115 


116  SUBMARINE   MINING. 

Rowlocks  are  forked  pieces  of  metal  in  which  the  leather 
of  the  oars  rests  while  pulling.  Swivel  rowlocks  are  mov- 
able, a  pin  on  the  rowlock  fitting  into  a  socket  in  the  gunwale. 

Thole  pins  are  pins  set  vertically  in  the  gunwale  and  are 
used  in  place  of  rowlocks. 

The  steering  rowlock  is  a  peculiar  form  of  swivel  rowlock 
(fitted  near  the  stern  of  a  boat)  in  which  the  steering  oar  is 
shipped.  This  is  sometimes  called  a  crutch. 

The  painter  is  a  rope  secured  in  the  bow  for  towing  or  for 
securing  the  boat. 

Boat-falls  are  tackles  made  with  two  blocks  and  a  length 
of  rope ;  used  for  hoisting  boats. 

The  plug  is  the  wooden  stopper  fitted  into  a  hole  in  the 
bottom  of  a  boat  to  let  water  in  or  out. 

A  boat  breaker  is  a  small  keg  used  for  carrying  fresh  water. 

A  boat-recall  is  an  understood  signal  made  to  order  a  boat's 
return. 

BOAT  ORDERS. 

Oars  and  rowlocks  having  been  placed  in  the  boat,  blades 
of  oars  toward  the  bow,  rudder  and  yoke,  if  any,  stepped  and 
the  yoke  lanyards  clear,  the  men  board  and  take  their  proper 
seats.  The  man  pulling  the  bow-oar  is  No.  1,  the  next  man 
is  No.  2,  and  so  on,  to  the  man  pulling  the  stern-oar,  who  is 
called  the  "stroke-oar."  The  men  being  seated,  with  oars 
handy,  the  bow-man,  who  may  be  No.  1  or  an  extra  man,  as 
convenient,  holds  onto  the  wharf,  side,  or  piling,  as  the  case 
may  be,  with  his  boat  hook. 

Shove  off. — At  this  command  the  bow-man  shoves  the  boat 
clear,  giving  her  headway  if  possible.  He  boats  his  boat 
hook  and  takes  his  seat. 

Up  oars. — The  crew  simultaneously  seize  and  raise  their 
oars  smartly  to  the  vertical  (guiding  on  the  stroke-oar)  and 
hold  them  directly  in  front  of  them,  the  blades  fore-and-aft, 
inboard  hands  grasping  the  handles,  holding  the  same  well 
down  between  the  knees,  outboard  hands  grasping  the  loom? 
at  the  height  of  the  chin. 

Let  fall. — The  oars  are  eased  down  into  the  rowlocks  to- 
gether, brought  level  with  the  gunwale,  blades  horizontal  and 


SUBMARINE    MINING.  117 

all  trimmed  on  the  after  oars.  Oars  must  not  be  allowed  to 
splash. 

(1)   Give  way  together,  (2)  GIVE  WAY. 

At  the  first  command  the  men  reach  well  forward,  blades 
nearly  vertical,  ready  for  the  stroke.  At  the  second  com- 
mand they  dip  their  oars  at  the  same  time  as  the  stroke  oar 
and  commence  rowing,  keeping  stroke  exactly  and  all  lifting 
their  blades  to  the  height  of  the  gunwale  on  the  return.  (Or 
higher  if  waves  render  this  necessary.) 

TO   MAKE  A  LANDING. 

In  running  alongside  a  vessel  or  up  to  a  float-stage  or 
wharf,  wThen  several  lengths  away  from  same,  give*  the  com- 
mand (while  the  oars  are  in  the  water),  IN  BOWS.  The 
bow  oarsman  (if  there  be  no  extra  man  in  the  bow)  finishes 
his  stroke,  then  "  tosses "  and  "  boats "  his  oar,  blade  to 
the  bow,  and  stands  ready  with  the  boat  hook  to  fend  off 
and  hold  the  landing.  When  there  is  sufficient  headway  to 
carry  the  boat  properly  to  the  landing,  give  the  command, 
WAY  ENOUGH.  This  order  is  given  while  the  oars  are 
in  the  water;  the  men  finish  the  stroke,  then  toss  and  boat 
their  oars  with  as  little  noise  as  possible.  The  oars  are  next 
the  rail,  the  after-oars  outboard  of  the  bow  oars.  If  the 
stroke  oarsman  is  provided  with  a  boat  hook,  he  grasps  it 
and  stands  ready  to  help  the  bow  man. 

If  it  be  desired  to  stop  rowing  temporarily,  give  the  pre- 
paratory command,  (1)  Stand  l>y  to  lay  on  oars,  at  which 
the  crew  pays  strict  attention.  Then,  when  ready,  give  (2) 
OARS.  At  this  command,  given  while  the  oars  are  in  the 
water,  the  crew  finishes  the  stroke  and  brings  the  oars  level 
with  the  gunwale,  blades  horizontal,  trimmed  on  the  after 
oars.  This  position  is  also  used  for  salutes,  as  noted  here- 
after. 

If  about  to  pass  so  close  to  another  boat  that  a  collision  of 
oars  seems  probable,  command  (1)  Trail,  (2)  OARS.  At  the 
second  command,  given  while  the  oars  are  in  the  water,  the 
men  finish  the  stroke,  and  then,  while  the  oars  are  still  in 
the  water,  by  lifting  the  handles  with  their  outboard  hands. 


118  SUBMARINE    MINING. 

the  looms  are  thrown  out  of  the  rowlocks.  The  men  carry 
their  hands  outboard  till  the  backs  of  their  wrists  rest  on  the 
rails  and  the  oars  trail  astern.  (This  movement  is  used  in 
shooting  bridges,  where  lack  of  head  room  precludes  tossing.} 

To  bring  the  oars  inboard,  command :  OARS. 

At  this  command  the  men  raise  the  handles,  lower  the 
looms  into  the  rowlocks,  and  then  raise  the  blades  out  of  the 
water  and  swing  the  oars  to  the  regular  position  of  Let  fall. 

In  order  to  turn  the  boat  short  around  (being  stationary 
or  nearly  so)  command:  (1)  Give  way,  starboard;  'back  port. 
(2)  GIVE  WAY;  or  (1)  Give  way,  port;  back,  starboard, 
(2)  GIVE  WAY.  The  crew  keeps  stroke  just  as  regularly 
as  in  pulling  straight  away.  As  soon  as  the  boat  points  in 
the  desired  direction  command:  (1)  Give  way  together,  (2) 
GIVE  WAY. 

If  it  be  desired  to  check  the  boat's  headway,  command: 
HOLD  WATER.  At  this  command  the  men  drop  their 
blades  vertically  into  the  water,  tops  of  blades  inclined 
slightly  forward,  inboard  hands  grasping  the  handles,  out- 
board arms  over  the  looms  to  steady  the  oars  against  the 
chest.  To  prepare  the  crew  for  rowing  command  OARS, 
at  which  they  resume  the  position  described  under  the  head- 
ing Let  fall. 

To  move  the  boat  astern  command  STERN  ALL. 

At  this  command  the  men  back  water,  keeping  stroke  as 
regularly  as  in  ordinary  rowing.  To  resume  the  position  of 
attention  give  the  command  OARS,  as  before. 

To  toss  oars  command:  (1)  Stand  ~by  to  toss,  (2)  TOSS. 

The  command  of  execution  is  given  while  the  oars  are  in 
the  water,  the  stroke  is  completed  and  the  oars  raised  smartly 
to  the  vertical,  with  blades  in  fore  and  aft  plane,  handles  of 
oars  on  bottom  boards,  the  wrists  of  the  inboard  hands  rest- 
ing on  the  thighs,  outboard  hands  grasping  the  looms  at  the 
height  of  the  chin,  crew  sitting  upright.  To  place  the  oars 
in  the  boat  give  the  command  BOAT  YOUR  OARS.  At 
this  command  the  oars  are  lowered  toward  the  bow  (not 
swung  outboard)  and  laid  in  the  boat  as  before  described. 
This  command  may  be  given  from  the  position  of  Let  fall, 
in  which  case  the  men  toss  their  oars  and  proceed  as  above. 


SUBMAKINE    MINING.  119 


NOTES. 


In  rowing  the  blade  of  the  oar  should  be  raised  as  high  as 
the  gunwale  after  leaving  the  water  and  feathered  by  drop- 
ping the  wrist.  A  barely  perceptible  pause  should  be  made, 
and  the  oar  next  thrown  well  forward  and  dropped  edgewise 
into  the  water,  taking  care  to  avoid  splashing  and  chopping. 
Now  swing  the  oar  smartly  through  the  water  without  giving 
it  any  final  jerk,  and  repeat  as  above.  With  green  crews  it 
may  be  found  necessary  for  the  coxswain  to  call  stroke,  stroke, 
in  order  to  get  the  men  to  pull  exactly  together. 

There  should  be  a  mark  on  the  loom  of  the  oar  (about  the 
height  of  the  eyes  when  the  oar  is  at  toss)  to  show  when  the 
blade  is  fore-and-aft,  thus  avoiding  the  necessity  of  the  men 
gazing  up  for  the  purpose  of  finding  out  when  this  is  the  case. 
Never  allow  a  boat's  crew  to  splash  with  the  blades  when 
executing  Let  fall.  When  resting  on  oars,  insist  that  they  be 
kept  level  with  the  gunwale  and  at  right  angles  to  the  keel. 
Talking  among  the  crew  and  turning  the  heads  to  look  at  any 
object  should  never  be  allowed  while  the  boat  is  under  way. 
In  most  cases,  boats  should  be  permanently  equipped  with  a 
small  breaker  of  fresh  water,  a  spare  oar  and  oarlock  and  a 
suitable  anchor  or  grapnel.  The  anchor  rope  to  withstand  a 
storm  should  be  six  (6)  times  as  long  as  the  greatest  depth 
liable  to  be  used  as  an  anchorage.  For  any  small  boat  in  our 
service  a  20-pound  anchor  and  12-thread  (about  1  inch) 
manila  hawser  should  easily  weather  a  hurricane.  A  boat 
should  never  go  out  at  night  without  a  good,  well-filled  lan- 
tern. Many  a  boat  has  been  run  down  through  its  inability 
to  make  its  presence  known.  Before  leaving  the  shore  in 
foggy  weather,  provide  the  boat  with  some  sort  of  a  foghorn 
and  a  compass,  and  calculate  as  nearly  as  possible  the  bear- 
ings of  the  landing  you  wish  to  make.  Take  the  opposite  of 
this  upon  returning,  making  due  allowance  for  tide  and  wind 
in  both  cases.  To  ride  out  a  gale  of  wind  in  an  open  boat, 
lash  the  oars  and  grating  together,  making  them  into  a 
bulky  bundle  and  weight  them  if  possible ;  span  them  with  the 
painter  and  pitch  them  overboarcL  This  will  keep  the  boat's 
head  to  the  sea  and  prevent  her  from  drifting  fast.  Assist 
the  boat  to  take  the  seas  head-on  by  means  of  a  steering  oar. 


120  SUBMARINE   MINING. 

In  rowing  through  a  chop,  where  the  rudder  is  apt  to  be 
pitched  clear  of  the  water,  it  should  be  unshipped  and  a  steer- 
ing oar  used  instead.  Remember,  in  making  a  landing,  that 
the  heavier  the  boat  is  laden  the  longer  she  will  keep  her  way. 
If  you  are  being  towed  by  a  steamer,  make  her  give  you  a 
line,  instead  of  using  your  own,  and  belay  it  so  it  can  be  cast 
off  in  a  hurry.  Carefully  avoid  weighing  down  the  bow; 
always  use  a  short  towline  when  the  boat  is  empty  and  a  long 
towline  when  the  boat  is  laden.  If  the  boat's  painter  is  used 
for  a  towline,  have  a  knife  ready  for  cutting  it  if  it  becomes 
necessary.  Never  go  close  under  a  steamer's  stern  unless  it 
is  absolutely  unavoidable. 

Officers  in  boarding  a  ship,  use  the  starboard  gangway, 
although  they  may  use  the  port  gangway.  Enlisted  men  use 
the  port  gangway  or  the  booms,  unless  otherwise  ordered. 

Boat  salutes. — The  following  salutes  should  be  exchanged 
between  boats  meeting  or  passing  each  other.  No  junior 
should  pass  ahead  of  a  senior  without  permission. 

The  junior  should  always  salute  first,  and  the  senior  should 
return  the  salute  by  touching  his  cap. 

Salutes  should  be  exchanged  whenever  boats  pass  near 
enough  to  each  other  for  the  senior  officer  to  be  recognized, 
whether  he  be  in  uniform  or  not. 

Officers  without  a  flag  or  pennant  flying  should  be  saluted 
with  the  hand  only;  those  with  a  flag  or  pennant  flying 
should,  in  addition,  be  saluted  by  laying  on  oars. 

When  a  noncommissioned  officer  is  in  a  boat  and  meets 
another  boat  containing  an  officer  he  stands  and  salutes.  If 
the  boat  flies  a  flag  or  pennant,  the  noncommissioned  officer, 
in  addition,  lays  on  oars. 

Officers  of  the  Navy  and  Marine  Corps  and  foreign  officers 
in  boats  should  always  be  saluted  when  recognized. 

In  laden  boats,  towing  boats,  or  boats  under  sail  the  hand 
salute  only  is  made  on  all  occasions. 

Coxswains  in  charge  of  boats  shall  always  rise  and  salute 
when  officers  enter  or  leave  their  boats. 

Boat  keepers  shall  stand  up  and  salute  officers  passing  in 
boats  and  remain  standing  until  the  boat  has  come  alongside 
or  passed. 


APPENDIX  NO.  8. 
SUPPLY  LIST. 

APPARATUS. 

Ammeters,  portable,  0-25  scale,  1  to  each  post. 
Anchors,  buoy,  500  pounds,  5  to  each  group  of  19  mines. 
Anchors,  mine,  1  to  each  buoyant  mine. 
Axle,  cable-reel,  1  to  each  cable-reel  frame. 
Balances  and  weights,  1  set  to  each  post. 
Battery,  storage,  1  to  each  casemate. 
Boards,  operating,  1  to  each  group  of  19  mines. 
Boxes,  distribution,  1  to  each  group  of  19  mines. 
Boxes,  distribution,  1  to  each  group  of  7  mines. 
Boxes,  junction,  large,  3  to  each  mile  of  multiple  cable. 
Boxes,  junction,  small,  1  to  each  mile  of  single-conductor  cable. 
Buoy,  distribution-box,  1  to  each  distribution  box. 
Buoy,  marking,  5  to  each  group  of  19  mines. 
Buoy,  mine,  1  to  each  buoyant  mine. 
Cable,  submarine,  19-conductor,  according  to  project. 
Cable,  submarine,  7-conductor,  according  to  project. 
Cable,  submarine,  1  conductor,  according  to  project. 
Cases,  gun  cotton,  as  required. 
Circuit  closer,  1  to  each  mine  transformer. 
Clips,  cable,  2  for  each  mine. 
Engine,  internal  combustion,  1  to  each  casemate. 
Frame,  cable-reel,  3  to  each  post. 
Fuse  can,  1  to  each  compound  plug. 
Generator,  casemate,  1  to  each  casemate. 
Mine  cases,  according  to  project. 
Motor  generator,  D.  C.-A.  C.,  2  to  each  casemate. 
Panels,  power,  1  to  each  casemate. 

Planting  equipment  for  emergency  vessels,  1  to  each  vessel : 
Each  planting  equipment  consists  of — 

1  axle,  cable-reel. 
4  blocks,  snatch. 

4  blocks,  triplex,  2-ton. 

2  corne-alongs. 

2  davits,  anchor. 
2  davits,  mine. 
1  frame,  cable-reel. 
4  hooks,  trip. 

121 


122  SUBMARINE   MINING. 

Plugs,  compound,  1  to  each  mine  case. 
Heels,  cable,  according  to  cable  on  hand. 
Reel  and  frame,  measuring,  1  to  each  mine  field. 
Shackles,  anchor,  2  to  each  anchor. 
Shackles,  mine,  2  to  each  mine. 
Sister  hooks,  1  pair  to  each  anchor. 

Sockets,  mooring,  2  to  each  buoyant  mine,  for  wire  rope  only. 
Springs,  automatic  anchor,  6  extra  for  each  group  of  19  mines. 
Switches,  starting,  1  to  each  motor  generator,  D.  C.-A.  C. 
Telephones,  boat,  4  to  each  mine  field. 

Testing  set,  insulation,  1  to  each  post  having  a  cable  tank : 
Each  testing  set  consists  of — 

1  box,  resistance,  100,000  ohms. 

2  cases  for  instruments. 

1  galvanometer,  D'Arsonval,  reflecting. 

1  key,  special  insulation  testing. 

1  repair  kit. 

1  shunt,  Ayrton  Universal. 
Transformer,  casemate,  2  to  each  casemate. 
Transformer,  mine,  1  to  each  mine. 

Voltmeter,  portable,  0-3-volt  scale,  1  to  each  storage  battery. 
Voltmeter,  portable,  0-150-volt  scale,  2  to  each  post. 
Weights,  distance,  for  automatic  anchor,  6  extra  for  each  group  of  19 
mines. 

UTENSILS. 

(Supply  for  each  post,  unless  otherwise  indicated.) 

1  anvil,  50-pound. 
3  axes,  handled. 
6  basins,  wash. 

24  binding  posts  (to  each  casemate). 

2  blocks,  tackle,  double. 
2  blocks,  tackle,  single. 
6  boxes,  tool. 

6  brushes,  battery. 

6  brushes,  dust. 

6  brushes,  paint,  flat. 

6  brushes,  paint,  oval. 

12  brushes,  sash. 

12  brushes,  scratch. 

6  buckets,  galvanized  iron. 

1  chest,  carpenter's  tool : 

The  chest  contains  the  following  tools — 

1  bits,  set,  of  13. 

1  bit,  expansive, 

1  brace,  ratchet. 

1  chisels,  carpenter's,  set  of  6. 


SUBMARINE   MINING.  123 

1  chest,  carpenter's  tool — Continued. 

The  chest  contains  the  following  tools — Continued. 

1  hammer,  claw. 

1  knife,  drawing. 

1  level,  carpenter's. 

1  oilstone. 

1  plane,  jack. 

1  plane,  smooth. 

1  rule,  2-foot. 

1  saw,  compass. 

1  saw,  hand. 

1  saw,  rip. 

1  saw  set. 

1  square,  carpenter's. 
6  chisels,  cold. 

4  clips,  wire  rope  (for  each  buoyant  mine). 
4  coppers,  soldering. 
3  crowbars. 
6  cups,  drinking. 

2  cutters,  cable. 

1  dies,  letters,  set. 

1  dies,  numbers,  set. 

1  drill,  breast. 

1  drill  points,  set  of  15. 

6  files,  6-inch,  flat  bastard. 

3  files,  6-inch,  slim  taper. 
6  funnels,  loading,  large. 
6  funnels,  loading,  small. 

1  gloves,  rubber,  pair  (to  each  storage  battery). 

1  grindstone. 

24  hacksaw  blades. 

4  hacksaw  frames. 

6  hammers,  ball  peen. 
6  hammers,  smith's. 

2  handles,  with  tools. 

3  hatchets. 

6  hooks,  boat. 

2  hydrometers,  battery  (to  each  storage  battery). 

3  irons,  calking. 

4  irons,  grappling. 

120  knives,  submarine  mine  (for  each  mine  company,  to  be  issued  as 

part  of  equipment). 
3  ladles. 
6  lamps,  alcohol. 

2  lamps,  battery  inspection  (to  each  storage  battery). 

3  lamps,  Khotal. 

5  leads,  sounding. 

M003°— 12 10 


124  SUBMARINE   MINING. 

12  levers  for  socket  wrenches. 

12  life  buoys. 

12  life-preservers. 

2  mallets,  large. 

2  mallets,  small. 

12  marlinspikes. 

6  megaphones. 

1  oilers  and  tray,  set  (to  each  casemate). 
12  padlocks,  brass,  with  chain. 

2  pitchers,  acid  (to  each  storage  battery). 

2  plates,  earth. 

70  pliers,  side  cutting,  5£  inch  (for  each  mine  company,  to  be  issued 

as  part  of  equipment). 
50  pliers,  side  cutting,  8-inch   (for  each  mine  company,  to  be  issued 

as  part  of  equipment). 

3  pots,  melting. 

4  pumps,  boat  (to  each  mine  field). 

2  scales,  extension  spring,  reading  200  pounds. 

1  scales,  portable  platform. 
6  scissors,  8-inch. 

6  scoops,  large,  for  trotol  only. 

6  scoops,  small,  for  trotol  only. 

12  scrapers,  iron,  with  handle. 

4  screw-drivers,  large. 

4  screw-drivers,  medium. 

4  screw-drivers,  small. 

6  switches,  assorted  (to  each  casemate). 

2  syringes,  battery  (to  each  storage  battery). 

3  tapes,  measuring. 

2  thermometers,  battery  (to  each  storage  battery). 

2  thermometers,  cable  tank. 

2  thimbles,  galvanized  iron  (to  each  buoyant  mine  case). 

2  tongs,  cable  reel. 

6  torches,  gasoline,  hand. 

2  trucks,  mine  case. 
6  vises,  bench,  large. 

6  wrenches,  monkey,  8-inch. 
6  wrenches,  monkey,  15-inch. 
12  wrenches,  S. 
6  wrenches,  socket. 
6  wrenches,  spanner. 

3  wrenches,  Still  son. 
6  wrenches,  T,  small. 

EXPENDABLE   STORES. 

Alcohol,  wood,  5  gallons  to  each  post. 

Antimony  for  socket  alloy,  10  pounds  to  each  19  mines. 

Books,  record  of  cable  test,  1  to  each  post. 


SUBMARINE   MINING.  125 

Books,  daily  test,  2  to  each  post. 

Books,  note,  24  to  each  post. 

Brushes,  carbon,  4  extra  for  each  machine  requiring  them. 

Brushes,  wire,  4  extra  for  each  machine  requiring  them. 

Cells,  dry,  large,  25  to  each  post. 

Cells,  dry,  small,  100  to  each  post. 

Cement,  rubber,  3  pounds  to  each  19  mines. 

Cleats,  porcelain,  1-wire,  50  to  each  casemate. 

Cleats,  porcelain,  2-wire,  50  to  each  casemate. 

Collars,  Turk's-head,  large,  10  to  each  mile  of  7-conductor  cable. 

Collars,  Turk's-head,  medium,  10  to  each  mile  of  19-conductor  cable. 

Collars,  Turk's-head,  small,  5  to  each  mine. 

Compound,  commutator,  1  stick  to  each  casemate. 

Connectors,  double,  25  to  each  casemate. 

Cords,  telephone,  4  extra. 

Crayons,  marking,  12  to  each  storehouse. 

Cut-outs,  porcelain,  2  to  each  casemate. 

Drier,  as  required. 

Electrolyte,  specific  gravity  1210,  4  carboys  to  each  casemate, 

Explosive,  according  to  project. 

Fuses,  service,  4  to  each  mine. 

Gasoline,  for  torches,  10  gallons  to  each  post. 

Glands  for  compound  plugs,  2  extra  for  each  plug. 

Glue,  5  pounds  to  each  post. 

Graphite,  as  required. 

Handles,  assorted,  as  required  for  repairing  tools. 

Insulators,  glass,  25  to  each  storehouse. 

Jointers,  copper,  1  pound  to  each  19  mines. 

Keys,  distribution  box,  flat,  4  extra  to  each  box. 

Keys,  distribution  box,  split,  4  extra  to  each  box. 

Keys,  mine  case,  2  extra  for  each  mine  case. 

Keys,  shackle,  1  extra  to  each  shackle. 

Knobs,  porcelain,  100  to  each  post. 

Lampblack,  2  pounds  to  each  100  pounds  of  white  lead. 

Lamps,  incandescent,  white,  110  volts,  16-candlepower,  12  to  each  case- 
mate. 

Lamps,  incandescent,  white,  80  volts,  16-candlepower,  12  to  each  case- 
mate. 

Lamps,  incandescent,  red,  80  volts,  8-candlepower,  3  to  each  operating 
board. 

Lamps,  incandescent,  green,  45  volts,  8-candlepower,  3  to  each  operat- 
ing board. 

Lamps,  incandescent,  green,  45  volts,  16-candlepower,  3  to  each  operat- 
ing board. 

Lamps,  incandescent,  green,  45  volts,  32-candlepower,  3  to  each  operat- 
ing board. 

Lead,  for  socket  alloy,  90  pounds  for  each  19  mines. 


126  SUBMARINE   MINING. 

Lead,  red,  as  required. 
Lead,  white,  as  required. 
Line,  cod,  2,000  feet  to  each  post. 
Line,  measuring,  2,000  feet  to  each  post. 
Line,  sounding,  500  feet  to  each  post. 
Lye,  as  required. 
Marline,  1  pound  to  each  mine. 
Nails,  assorted  sizes,  25  pounds  to  each  post. 
Needles,  cleaning,  for  Khotal  lamps,  6  to  each  post. 
Nipples,  soft  rubber,  1  to  each  hard-rubber  fuze  can. 
Oakum,  50  pounds  to  each  post. 
Oil,  cylinder,  5  gallons  to  each  casemate. 
Oil,  dynamo,  1  gallon  to  each  casemate. 
Oil,  lubricating,  1  gallon  to  each  storehouse. 
Oil,  linseed,  as  required,  3  gallons  to  100  pounds  of  lead. 
Oil,  slushing,  5  gallons  to  each  post. 
Oil,  tar,  as  required  for  marline-covered  rope. 
Oil,  transformer,  1  gallon  to  each  casemate  transformer. 
Packing,  asbestos  sheet,  2  pounds  to  each  casemate. 
Packing,  asbestos  wick,  1  pound  to  each  casemate. 
Packings,  rubber,  100  to  each  19  mines. 
Paint,  acid-resisting,  as  required. 

Paint,  steel  color,  for  casemate  apparatus,  as  required. 
Paste,  soldering,  1  pound  to  each  post. 
Paraffin,  10  pounds  to  each  post. 
Pencils,  lead,  6  dozen  to  each  post. 
Plugs,  attachment,  6  to  each  post. 
Pomade,  Putz,  3  pounds  to  each  post. 
Primers,  explosive,  1  to  each  mine  charge. 
Pumice  stone,  2  pounds  to  each  casemate. 
Resin,  2  pounds  to  each  post. 

Rope,  for  distance  weight,  20  feet  for  each  automatic  anchor. 
Rope  for  heaving  lines,  1,200  feet  to  each  post. 
Rope  for  lashings,  1,200  feet  to  each  post. 
Rope,  marline  covered,  according  to  project. 
Rope,  raising,  50  per  cent  more  than  of  mooring  rope. 
Rope,  wire-mooring,  according  to  project. 
Rosettes,  24  to  each  post. 
Ruberine,  5  gallons  to  each  post. 
Sandpaper,  48  sheets  to  each  post. 
Sapolio,  10  cakes  to  each  post. 

Screws,  brass,  assorted  sizes,  1  gross  when  required. 
Screws,  iron,  assorted  sizes,  1  gross  when  required. 
Screws,  set,  for  compound  plugs,  1  extra  set  for  each  compound  plug. 
Screws,  set,  for  mine  transformers,  1  extra  set  for  each  mine  trans- 
former. 


SUBMARINE   MINING.  127 

Shellac  for  insulation  purposes,  5  pounds  to  each  post. 

Soap,  25  cakes  to  each  post. 

Sockets,  lamp,  12  to  each  casemate. 

Solder,  wire,  5  pounds  to  each  post. 

Staples,  large,  20  pounds  to  each  post. 

Staples,  small,  1  pound  to  each  post. 

Suspensions,  galvanometer,  lower,  3  to  each  insulation  testing  set. 

Suspensions,  galvanometer,  upper,  6  to  each  insulation  testing  set. 

Tags,  brass,  50  per  group  of  19  mines. 

Tags,  lead,  50  per  group  of  19  mines. 

Tags,  linen,  50  per  group  of  19  mines. 

Tape,  protective,  5  pounds  to  each  19  mines. 

Tape,  rubber.  5  pounds  to  each  19  mines. 

Tinfoil,  1  pound  to  each  19  mines. 

Towelling,  10  yards  to  each  post. 

Tubes,  porcelain,  12  to  each  post. 

Turpentine,  as  required. 

Twine,  3  pounds  to  each  19  mines. 

Varnish,  asphaltum,  as  required. 

Varnish,  spar,  as  required. 

Washers,  brass,  100  to  each  19  mines. 

Washers,  lead,  1  extra  set  for  each  compound  plug. 

Waste,  cotton,  50  pounds  to  each  post. 

Wire,  casemate,  extra,  100  feet  each  of  black,  blue,  red,  and  brown 

to  each  casemate. 

Wire,  fuse,  1  pound  each  of  3,  12,  and  25  ampere  to  each  casemate. 
Wire,  lamp-cord,  extra  100  feet  to  each  casemate. 
Wire,  loading,  20  feet  to  each  mine. 
Wire,  soft  drawn  copper. 

Remarks: 

(a)  Clips  and  thimbles,  scales,  extension  spring,  marline- 
covered  rope,  and  parts  for  automatic  anchors  are  required 
only  at  posts  supplied  with  automatic  anchors. 

(&)  Loading  scoops  are  required  only  at  posts  supplied 
with  trotol. 

(c)  In  the  case  of  articles  to  be  supplied  "  as  required  " 
it  is  not  contemplated  that  they  shall  be  kept  on  hand  in 
larger  quantities  than  required  for  immediate  needs. 


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